avcodec/sheervideo: reduce size of vlc tables to normal values

libavcodec/sheervideo.c

@@ -1795,7 +1795,7 @@ static int build_vlc(VLC *vlc, const uint8_t *len, int count)
     }
 
     ff_free_vlc(vlc);
-    return ff_init_vlc_sparse(vlc, 16, count,
+    return ff_init_vlc_sparse(vlc, 12, count,
                               bits,  sizeof(*bits),  sizeof(*bits),
                               codes, sizeof(*codes), sizeof(*codes),
                               syms,  sizeof(*syms),  sizeof(*syms), 0);