gpu_thread: Disable flush on read on normal GPU accuracy

This is an unfortunate oversight when adding more GPU accuracies. It
makes no sense to be more accurate (and fail to do so) in normal
accuracy than in high.

I plan to merge Normal and High in the same setting in the future.

src/video_core/gpu_thread.cpp

@@ -106,14 +106,10 @@ void ThreadManager::FlushRegion(VAddr addr, u64 size) {
         PushCommand(FlushRegionCommand(addr, size));
         return;
     }
-
     // Asynchronous GPU mode
     switch (Settings::values.gpu_accuracy.GetValue()) {
     case Settings::GPUAccuracy::Normal:
-        PushCommand(FlushRegionCommand(addr, size));
-        break;
     case Settings::GPUAccuracy::High:
-        // TODO(bunnei): Is this right? Preserving existing behavior for now
         break;
     case Settings::GPUAccuracy::Extreme: {
         auto& gpu = system.GPU();