avutil/intmath: fix undefined behavior in ff_ctzll_c()

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

libavutil/intmath.h

@@ -131,7 +131,7 @@ static av_always_inline av_const int ff_ctzll_c(long long v)
         63, 52, 6, 26, 37, 40, 33, 47, 61, 45, 43, 21, 23, 58, 17, 10,
         51, 25, 36, 32, 60, 20, 57, 16, 50, 31, 19, 15, 30, 14, 13, 12
     };
-    return debruijn_ctz64[(uint64_t)((v & -v) * 0x022FDD63CC95386D) >> 58];
+    return debruijn_ctz64[(uint64_t)((v & -v) * 0x022FDD63CC95386DU) >> 58];
 }
 #endif