[client] main: remove/fix faulty upsTime code

The implementation was flawed, instead we just update the presentation
time if there was not an early wakeup.

client/src/main.h

@@ -104,7 +104,7 @@ struct AppState
   RingBuffer            renderTimings;
   RingBuffer            frameTimings;
 
-  atomic_uint_least64_t renderCount, frameCount, upsTime;
+  atomic_uint_least64_t renderCount, frameCount;
   _Atomic(float)        fps, ups;
 
   uint64_t resizeTimeout;