Fixes: Timeout
Fixes: 8665/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_CSCD_fuzzer-5768442610188288

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
(cherry picked from commit 78167b49)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>