ffplay: remove redundant prototype

Signed-off-by: Lukasz Marek <lukasz.m.luki@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
dxva2: bump maximum number of slieces for mpeg2

Suggested by heleppkes on https://trac.ffmpeg.org/ticket/3133

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Fix decoding of some 8 < bpc < 16 signed j2k samples with libopenjpeg.

No testcase known.

Reviewed-by: Michael Bradshaw