avcodec/jpeg2000dsp: Fix integer overflows in ict_int()

Fixes: signed integer overflow: 46802 * -71230 cannot be represented in type 'int'
Fixes: 4756/clusterfuzz-testcase-minimized-4812495563784192

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

libavcodec/jpeg2000dsp.c

@@ -64,9 +64,9 @@ static void ict_int(void *_src0, void *_src1, void *_src2, int csize)
     int i;
 
     for (i = 0; i < csize; i++) {
-        i0 = *src0 + *src2 + (((26345 * *src2) + (1 << 15)) >> 16);
+        i0 = *src0 + *src2 + ((int)((26345U * *src2) + (1 << 15)) >> 16);
         i1 = *src0 - ((int)(((unsigned)i_ict_params[1] * *src1) + (1 << 15)) >> 16)
-                   - (((i_ict_params[2] * *src2) + (1 << 15)) >> 16);
+                   - ((int)(((unsigned)i_ict_params[2] * *src2) + (1 << 15)) >> 16);
         i2 = *src0 + (2 * *src1) + ((int)((-14942U * *src1) + (1 << 15)) >> 16);
         *src0++ = i0;
         *src1++ = i1;