av_buffersrc_add_ref: fix permissions

fix delogo fate
Revert "rawdec: use AVPALETTE_SIZE instead of magic constants."

This reverts commit ba35f2eda0c3c3c8c6fa9df5bd9225a2038eae52.

This fixes decoding of 4bpp.mov

Conflicts:

	libavcodec/rawdec.c
fate: disable sub2video

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