avcodec/sbrdsp_fixed: Fix integer overflows in sbr_qmf_deint_neg_c()

Fixes: signed integer overflow: 2147483645 + 16 cannot be represented in type 'int'
Fixes: 46993/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_AAC_FIXED_fuzzer-4759025234870272

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 1537f405)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/sbrdsp_fixed.c

@@ -114,8 +114,8 @@ static void sbr_qmf_deint_neg_c(int *v, const int *src)
 {
     int i;
     for (i = 0; i < 32; i++) {
-        v[     i] = ( src[63 - 2*i    ] + 0x10) >> 5;
-        v[63 - i] = (-src[63 - 2*i - 1] + 0x10) >> 5;
+        v[     i] = (int)(0x10U + src[63 - 2*i    ]) >> 5;
+        v[63 - i] = (int)(0x10U - src[63 - 2*i - 1]) >> 5;
     }
 }