net: amd-xgbe: fix clang -Wformat warning

see warning:
| drivers/net/ethernet/amd/xgbe/xgbe-drv.c:2787:43: warning: format specifies
| type 'unsigned short' but the argument has type 'int' [-Wformat]
|        netdev_dbg(netdev, "Protocol: %#06hx\n", ntohs(eth->h_proto));
|                                      ~~~~~~     ^~~~~~~~~~~~~~~~~~~

Variadic functions (printf-like) undergo default argument promotion.
Documentation/core-api/printk-formats.rst specifically recommends
using the promoted-to-type's format flag.

Also, as per C11 6.3.1.1:
(https://www.open-std.org/jtc1/sc22/wg14/www/docs/n1548.pdf)
`If an int can represent all values of the original type ..., the
value is converted to an int; otherwise, it is converted to an
unsigned int. These are called the integer promotions.`

Since the argument is a u16 it will get promoted to an int and thus it is
most accurate to use the %x format specifier here. It should be noted that the
`#6` formatting sugar does not alter the promotion rules.

Link: ClangBuiltLinux/linux#378
Signed-off-by: Justin Stitt <[email protected]>
Reviewed-by: Nick Desaulniers <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

drivers/net/ethernet/amd/xgbe/xgbe-drv.c

@@ -2784,7 +2784,7 @@ void xgbe_print_pkt(struct net_device *netdev, struct sk_buff *skb, bool tx_rx)
 
 	netdev_dbg(netdev, "Dst MAC addr: %pM\n", eth->h_dest);
 	netdev_dbg(netdev, "Src MAC addr: %pM\n", eth->h_source);
-	netdev_dbg(netdev, "Protocol: %#06hx\n", ntohs(eth->h_proto));
+	netdev_dbg(netdev, "Protocol: %#06x\n", ntohs(eth->h_proto));
 
 	for (i = 0; i < skb->len; i += 32) {
 		unsigned int len = min(skb->len - i, 32U);