Remove async and non-blocking page flip support

It doesn't work well in practice for a few major reasons:
- It can result in the decoder writing on DMA-BUFs being used by the display
- It can generate page flip events that collide with Qt/SDL
- It can stall the decoder if the DMA-BUF has a fence on it from the display driver

app/streaming/video/ffmpeg-renderers/drm.cpp

@@ -164,7 +164,6 @@ DrmRenderer::~DrmRenderer()
             m_PropSetter.disablePlane(m_OverlayPlanes[i]);
         }
         m_PropSetter.apply();
-        m_PropSetter.waitForFlipCompletion();
     }
 
     for (int i = 0; i < k_SwFrameCount; i++) {
@@ -495,7 +494,7 @@ bool DrmRenderer::initialize(PDECODER_PARAMETERS params)
         atomic = true;
     }
 
-    m_PropSetter.initialize(m_DrmFd, atomic, !params->enableVsync);
+    m_PropSetter.initialize(m_DrmFd, atomic);
 
     drmModePlaneRes* planeRes = drmModeGetPlaneResources(m_DrmFd);
     if (planeRes == nullptr) {