avcodec/diracdec: Fix integer overflow in INTRA_DC_PRED()

Fixes: runtime error: signed integer overflow: 1168175789 + 1168178473 cannot be represented in type 'int'
Fixes: 3081/clusterfuzz-testcase-minimized-4807564879462400
Fixes: 2844/clusterfuzz-testcase-minimized-5561715838156800

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

libavcodec/diracdec.c

@@ -586,7 +586,7 @@ static inline void codeblock(DiracContext *s, SubBand *b,
     } \
 
 INTRA_DC_PRED(8, int16_t)
-INTRA_DC_PRED(10, int32_t)
+INTRA_DC_PRED(10, uint32_t)
 
 /**
  * Dirac Specification ->