Tweak PS4 non-hack report timer (#903)

* try an aggressive forced report timer

* change the PS4 keepalive timer to 5ms

the synthetic results at 2ms were pretty good, just a bit too high of a
stddev (compared to other modes) for my liking. I think 5ms will do what
I want (multiple forced reports when idle per 60 Hz frame) without
harming real-world usage.

2ms results for posterity (three runs of WydD):

min: 0.55
max: 2.38
average: 0.97
stddev: 0.38

min: 0.55
max: 2.24
average: 0.97
stddev: 0.38

min: 0.55
max: 2.38
average: 0.99
stddev: 0.38

5ms should scoot the average and stddev down a bit.

src/drivers/ps4/PS4Driver.cpp

@@ -14,7 +14,7 @@
 #include "enums.pb.h"
 
 // force a report to be sent every X ms
-#define PS4_KEEPALIVE_TIMER 250
+#define PS4_KEEPALIVE_TIMER 5
 
 void PS4Driver::initialize() {
     //touchpadData = {