rendervulkan: Fix getting Vulkan DRM formats on SDL backend

[laurirasanen]

After commit 0110109 running gamescope nested SDL backend on top of x11 plasma causes assertion in wlroots. Related to issue #1218 but on devices that do support the DRM formats.

[gamescope] [Info]  console: gamescope version 3.15.9-10-g6497b0f (gcc 14.2.1)
No CAP_SYS_NICE, falling back to regular-priority compute and threads.
Performance will be affected.
[gamescope] [Info]  vulkan: selecting physical device 'AMD Radeon RX 6800 XT (RADV NAVI21)': queue family 1 (general queue family 0)
[gamescope] [Info]  vulkan: physical device supports DRM format modifiers
[gamescope] [Info]  wlserver: [backend/headless/backend.c:67] Creating headless backend
[gamescope] [Info]  vulkan: supported DRM formats for sampling usage:
[gamescope] [Info]  vulkan: Creating Gamescope nested swapchain with format 44 and colorspace 0
gamescope: types/wlr_linux_dmabuf_v1.c:532: feedback_compile: Assertion `table_len > 0' failed.
zsh: IOT instruction (core dumped)  ./build/src/gamescope -- glxgears

(gdb) bt
#0  0x00007ffff73b63f4 in ?? () from /usr/lib/libc.so.6
#1  0x00007ffff735d120 in raise () from /usr/lib/libc.so.6
#2  0x00007ffff73444c3 in abort () from /usr/lib/libc.so.6
#3  0x00007ffff73443df in ?? () from /usr/lib/libc.so.6
#4  0x00007ffff7355177 in __assert_fail () from /usr/lib/libc.so.6
#5  0x00005555557f0472 in feedback_compile (feedback=0x7fffffffda20) at ../subprojects/wlroots/types/wlr_linux_dmabuf_v1.c:532
#6  0x00005555557f131d in set_default_feedback (linux_dmabuf=0x555555b19770, feedback=0x7fffffffda20)
    at ../subprojects/wlroots/types/wlr_linux_dmabuf_v1.c:888
#7  0x00005555557f170e in wlr_linux_dmabuf_v1_create (display=0x7fffe44f2eb0, version=4, default_feedback=0x7fffffffda20)
    at ../subprojects/wlroots/types/wlr_linux_dmabuf_v1.c:971
#8  0x00005555557f1806 in wlr_linux_dmabuf_v1_create_with_renderer (display=0x7fffe44f2eb0, version=4, renderer=0x555555b19970)
    at ../subprojects/wlroots/types/wlr_linux_dmabuf_v1.c:1002
#9  0x00005555557c656a in wlr_renderer_init_wl_display (r=0x555555b19970, wl_display=0x7fffe44f2eb0) at ../subprojects/wlroots/render/wlr_renderer.c:87
#10 0x000055555563c225 in wlserver_init () at ../src/wlserver.cpp:1738
#11 0x00005555556344f5 in main (argc=1, argv=0x7fffffffdd28) at ../src/main.cpp:934

I'm not entirely sure what the intended behavior here is for backends that have UsesModifiers() set to false, but running on a device that supports them.

This PR returns the vulkan DRM format handling to what it was previously. i.e. they get added if supported by the device even if backend doesn't use them.

[gamescope] [Info]  console: gamescope version 3.15.9-10-g6497b0f (gcc 14.2.1)
No CAP_SYS_NICE, falling back to regular-priority compute and threads.
Performance will be affected.
[gamescope] [Info]  vulkan: selecting physical device 'AMD Radeon RX 6800 XT (RADV NAVI21)': queue family 1 (general queue family 0)
[gamescope] [Info]  vulkan: physical device supports DRM format modifiers
[gamescope] [Info]  wlserver: [backend/headless/backend.c:67] Creating headless backend
[gamescope] [Info]  vulkan: supported DRM formats for sampling usage:
[gamescope] [Info]  vulkan:   AR24 (0x34325241)
[gamescope] [Info]  vulkan:   XR24 (0x34325258)
[gamescope] [Info]  vulkan:   AB24 (0x34324241)
[gamescope] [Info]  vulkan:   XB24 (0x34324258)
[gamescope] [Info]  vulkan:   RG16 (0x36314752)
[gamescope] [Info]  vulkan:   NV12 (0x3231564E)
[gamescope] [Info]  vulkan:   AB4H (0x48344241)
[gamescope] [Info]  vulkan:   XB4H (0x48344258)
[gamescope] [Info]  vulkan:   AB48 (0x38344241)
[gamescope] [Info]  vulkan:   XB48 (0x38344258)
[gamescope] [Info]  vulkan:   AB30 (0x30334241)
[gamescope] [Info]  vulkan:   XB30 (0x30334258)
[gamescope] [Info]  vulkan:   AR30 (0x30335241)
[gamescope] [Info]  vulkan:   XR30 (0x30335258)
[gamescope] [Info]  vulkan: Creating Gamescope nested swapchain with format 44 and colorspace 0
[gamescope] [Info]  wlserver: Using explicit sync when available
[gamescope] [Info]  wlserver: Running compositor on wayland display 'gamescope-0'
[gamescope] [Info]  wlserver: [backend/headless/backend.c:17] Starting headless backend
[gamescope] [Info]  wlserver: Successfully initialized libei for input emulation!
[gamescope] [Error] wlserver: [xwayland/sockets.c:64] Failed to bind socket @/tmp/.X11-unix/X0: Address already in use
[gamescope] [Info]  wlserver: [xwayland/server.c:107] Starting Xwayland on :1
[gamescope] [Info]  pipewire: stream state changed: connecting
[gamescope] [Info]  pipewire: stream state changed: paused
[gamescope] [Info]  pipewire: stream available on node ID: 104
[gamescope] [Info]  vblank: Using timerfd.
[gamescope] [Info]  vulkan: Creating Gamescope nested swapchain with format 44 and colorspace 0
[gamescope] [Warn]  xwm: got the same buffer committed twice, ignoring.
The XKEYBOARD keymap compiler (xkbcomp) reports:
> Warning:          Unsupported maximum keycode 708, clipping.
>                   X11 cannot support keycodes above 255.
> Warning:          Could not resolve keysym XF86KbdInputAssistPrevgrou
> Warning:          Could not resolve keysym XF86KbdInputAssistNextgrou
Errors from xkbcomp are not fatal to the X server
Running synchronized to the vertical refresh.  The framerate should be
approximately the same as the monitor refresh rate.
828 frames in 5.0 seconds = 165.470 FPS