avcodec/ffwavesynth: use uint32_t to compute difference, it is enough
Fixes: signed integer overflow:
6494225984479297536 - -
6043795377581187040 cannot be represented in type 'long'
Fixes: 15285/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_FFWAVESYNTH_fuzzer-
5632780307791872
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
e9dd3c7126097d7c8d4f137db9957b81a219aa2c)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>