avcodec/ylc: Fix shift overflow

Fixes: runtime error: shift exponent 32 is too large for 32-bit type 'unsigned int'
Fixes: 2698/clusterfuzz-testcase-minimized-4713541443518464

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 03a9e6ff30)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/ylc.c

@@ -68,7 +68,7 @@ static void get_tree_codes(uint32_t *bits, int16_t *lens, uint8_t *xlat,
 
     s = nodes[node].sym;
     if (s != -1) {
-        bits[*pos] = (~pfx) & ((1U << FFMAX(pl, 1)) - 1);
+        bits[*pos] = (~pfx) & ((1ULL << FFMAX(pl, 1)) - 1);
         lens[*pos] = FFMAX(pl, 1);
         xlat[*pos] = s + (pl == 0);
         (*pos)++;