[FFmpeg-cvslog] avcodec/h264_slice: Fix integer overflow with last_poc

ffmpeg | branch: release/3.3 | Michael Niedermayer | Sat Apr 7 00:34:25 2018 +0200| [41458534aa8890810b678bcdb4c1c04f38b72231] | committer: Michael Niedermayer avcodec/h264_slice: Fix integer overflow with last_poc Fixes: signed integer overflow: 2147483646 - -2816

[FFmpeg-cvslog] avcodec/h264_slice: Fix integer overflow with last_poc

ffmpeg | branch: master | Michael Niedermayer | Sat Apr 7 00:34:25 2018 +0200| [8c02cd8ca097871dcd00cf8e08ce51660873f405] | committer: Michael Niedermayer avcodec/h264_slice: Fix integer overflow with last_poc Fixes: signed integer overflow: 2147483646 - -2816 cannot