avcodec/jpeg2000dwt: Fix integer overflows in sr_1d97_int()

Fixes: runtime error: signed integer overflow: 1157259380 + 1157259380 cannot be represented in type 'int'
Fixes: 2365/clusterfuzz-testcase-minimized-6020421927305216

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