Allow for more kernel book-keeping budget.

Looke like modern kernels starve earlier if not given enough
time to escape from realtime tasks. Increase the 1ms allowed budget
to 10ms, which should still be under a visible threshold.

lib/gpio.cc

@@ -500,8 +500,8 @@ static void DisableRealtimeThrottling() {
   if (GetNumCores() == 1) return;   // Not safe if we don't have > 1 core.
   // We need to leave the kernel a little bit of time, as it does not like
   // us to hog the kernel solidly. The default of 950000 leaves 50ms that
-  // can generate visible flicker, so we reduce that to 1ms.
-  WriteTo("/proc/sys/kernel/sched_rt_runtime_us", "999000");
+  // can generate visible flicker, so we reduce that to 10ms.
+  WriteTo("/proc/sys/kernel/sched_rt_runtime_us", "990000");
 }
 
 bool Timers::Init() {