qt: remove the timeout in `CompositorDirectComposition::setupVoutWindow()`

When m_setupStateCond.wait() is called, the scene graph has already started to initialize itself. So, 2.5 seconds waiting time was considered to be fair.

2.5 seconds were enough for Nvidia and VirtualBox drivers. However, it turns out that AMD needs more time.

This is mainly relevant when the application starts with a video.

Request review @chub.