avcodec/jpeg2000dsp: Reorder operations in ict_int() to avoid 2 integer overflows

Fixes: runtime error: signed integer overflow: 58065 * 51981 cannot be represented in type 'int'
Fixes: 2271/clusterfuzz-testcase-minimized-5778297776504832

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