avcodec/dnxhddec: Fix runtime error: left shift of negative value

Fixes: 2abd25478c62a675f335fac00b467023/asan_static-oob_10aff98_1227_8811480c6ef1e970a7977ceb7e5a9958.mxf

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/dnxhddec.c

@@ -361,7 +361,7 @@ static av_always_inline int dnxhd_decode_dct_block(const DNXHDContext *ctx,
         LAST_SKIP_BITS(bs, &row->gb, len);
         sign  = ~level >> 31;
         level = (NEG_USR32(sign ^ level, len) ^ sign) - sign;
-        row->last_dc[component] += level << dc_shift;
+        row->last_dc[component] += level * (1 << dc_shift);
     }
     block[0] = row->last_dc[component];