Fix GroupMutex and Clock Rescaling

This commit mainly fixes GroupMutex and clock rescaling. In addition, clock rescaling is no longer performed if the CNTFRQ_EL0 of the host device is same as that of the Switch (19.2MHz) which is fairly common on higher end devices.

app/src/main/cpp/skyline/gpu/display.cpp

@@ -62,7 +62,7 @@ namespace skyline::gpu {
                     break;
                 }
             }
-            sched_yield();
+            asm("yield");
         }
         struct {
             u32 slot;