vdpau/chroma: avoid cascading errors when mixer creation fails
vdpau/chroma: remove dead code and simplify
vdpau/chroma: fix leak on error
vdpau/chroma: remove one callback
vdpau/display: request reoriented video
vdpau/chroma: reorient the video (fixes #11068)
transcode: disable hardware decoding by default

It can still be enabled manually in the preferences as in previous
versions. Only it will not be used with the default ("auto") setting.