Revert "Merge commit of 'vdpau: remove old-style decoders'"

This reverts commit bf36dc50ea448999c8f8c7a35f6139a7040f6275, reversing
changes made to b7fc2693c70fe72936e4ce124c802ac23857c476.

Conflicts:

	libavcodec/h264.c

Keeping support for the old VDPAU API has been requested by our VDPAU maintainer

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec: fix compilation without vdpau

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>