avcodec/dirac_dwt: Fix integer overflow in COMPOSE_FIDELITYi*()

Fixes: runtime error: signed integer overflow: 161 * 13872281 cannot be represented in type 'int'

Fixes: 3295/clusterfuzz-testcase-minimized-4738998142500864

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 67da2685e0)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/dirac_dwt.h

@@ -102,10 +102,10 @@ void ff_spatial_idwt_slice2(DWTContext *d, int y);
     (b0 + b1)
 
 #define COMPOSE_FIDELITYiL0(b0, b1, b2, b3, b4, b5, b6, b7, b8)\
-    (b4 - ((-8*(b0+b8) + 21*(b1+b7) - 46*(b2+b6) + 161*(b3+b5) + 128) >> 8))
+    (b4 - ((int)(-8*(b0+(unsigned)b8) + 21*(b1+(unsigned)b7) - 46*(b2+(unsigned)b6) + 161*(b3+(unsigned)b5) + 128) >> 8))
 
 #define COMPOSE_FIDELITYiH0(b0, b1, b2, b3, b4, b5, b6, b7, b8)\
-    (b4 + ((-2*(b0+b8) + 10*(b1+b7) - 25*(b2+b6) + 81*(b3+b5) + 128) >> 8))
+    (b4 + ((int)(-2*(b0+(unsigned)b8) + 10*(b1+(unsigned)b7) - 25*(b2+(unsigned)b6) +  81*(b3+(unsigned)b5) + 128) >> 8))
 
 #define COMPOSE_DAUB97iL1(b0, b1, b2)\
     (b1 - ((int)(1817*(b0 + (unsigned)b2) + 2048) >> 12))