Use a separate callback to indicate EOS instead of renderFrame()

app/streaming/video/ffmpeg-renderers/dxva2.cpp

@@ -978,11 +978,6 @@ int DXVA2Renderer::getDecoderColorspace()
 
 void DXVA2Renderer::renderFrame(AVFrame *frame)
 {
-    if (frame == nullptr) {
-        // End of stream - nothing to do for us
-        return;
-    }
-
     IDirect3DSurface9* surface = reinterpret_cast<IDirect3DSurface9*>(frame->data[3]);
     HRESULT hr;