avcodec/ra144: Fix runtime error: signed integer overflow: -2200 * 1033073 cannot be represented in type 'int'

Fixes: 2175/clusterfuzz-testcase-minimized-5809657849315328

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

libavcodec/ra144.c

@@ -1601,7 +1601,7 @@ void ff_eval_coefs(int *coefs, const int *refl)
         b1[i] = refl[i] * 16;
 
         for (j=0; j < i; j++)
-            b1[j] = ((refl[i] * b2[i-j-1]) >> 12) + b2[j];
+            b1[j] = ((int)(refl[i] * (unsigned)b2[i-j-1]) >> 12) + b2[j];
 
         FFSWAP(int *, b1, b2);
     }