avcodec/jpeg2000: Check sum of sizes of band->prec before allocating

Fixes: OOM
Fixes: 4810/clusterfuzz-testcase-minimized-6034253235093504

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