avcodec/apedec: Use 64bit to avoid overflow

Fixes: runtime error: signed integer overflow: 727298502 * 3 cannot be represented in type 'int'
Fixes: 39172/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_APE_fuzzer-638602483033702

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 f059b561)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>