Such low resolution would result in empty output as a minimum of 4x4 is needed
We could also check for multiple of 4 dimensions but that is not needed

Fixes: Timeout
Fixes: 11191/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MSVIDEO1_fuzzer-5739529588178944

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpegSigned-off-by: Michael Niedermayer <michael@niedermayer.cc>