avcodec/x86/hevc_mc: fix sse register counts

These fix failures of --enable-xmm-clobber-test
It would be better to change the code to use fewer registers, but until
someone does the used register count must not be too small

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/libxavs: fix division by 0 bitrate

Fixes CID1257655

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