Fixes: signed integer overflow: 2021654528 + 2032575680 cannot be represented in type 'int'
Fixes: 16270/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_APE_fuzzer-5732438816325632

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