avcodec/wmalosslessdec: Fix integer overflow in mclms_predict()

Fixes: signed integer overflow: 2147483636 + 2048 cannot be represented in type 'int'
Fixes: 22016/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WMALOSSLESS_fuzzer-5109395618004992

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 c42ed06695)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/wmalosslessdec.c

@@ -675,7 +675,7 @@ static void mclms_predict(WmallDecodeCtx *s, int icoef, int *pred)
         for (i = 0; i < ich; i++)
             pred[ich] += s->channel_residues[i][icoef] *
                          s->mclms_coeffs_cur[i + num_channels * ich];
-        pred[ich] += (1 << s->mclms_scaling) >> 1;
+        pred[ich] += (1U << s->mclms_scaling) >> 1;
         pred[ich] >>= s->mclms_scaling;
         s->channel_residues[ich][icoef] += (unsigned)pred[ich];
     }