DVDVideoCodecFFmpeg: drop special handling for vdpau
vdpau: move vdpau into hwaccel
ffmpeg backport: register vdpau hwaccel for mpeg12
ffmpeg backport: fix vdpau vc1 interlace modes
ffmpeg: add patches for backports
Merge pull request #2699 from FernetMenta/hwaccel

move vdpau into hwaccel