avcodec/ra144: Fixes runtime error: signed integer overflow: 7160 * 327138 cannot be represented in type 'int'

Fixes: 1908/clusterfuzz-testcase-minimized-5392712477966336

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 08cb69e870)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/ra144.c

@@ -1512,7 +1512,7 @@ static void add_wav(int16_t *dest, int n, int skip_first, int *m,
 
     v[0] = 0;
     for (i=!skip_first; i<3; i++)
-        v[i] = (ff_gain_val_tab[n][i] * m[i]) >> ff_gain_exp_tab[n];
+        v[i] = (ff_gain_val_tab[n][i] * (unsigned)m[i]) >> ff_gain_exp_tab[n];
 
     if (v[0]) {
         for (i=0; i < BLOCKSIZE; i++)