Fixes: signed integer overflow: 15244032 * 256 cannot be represented in type 'int'
Fixes: 43504/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_CFHD_fuzzer-4865014842916864
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit cd6ac013a00373126bf3d313743d39b5edd5428a)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>