avcodec/pixlet: Fixes: undefined shift in av_mod_uintp2()

Fixes: runtime error: shift exponent 4294967289 is too large for 32-bit type 'int'
Fixes: 3030/clusterfuzz-testcase-minimized-4649809254285312

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

libavcodec/pixlet.c

@@ -262,7 +262,7 @@ static int read_high_coeffs(AVCodecContext *avctx, uint8_t *src, int16_t *dst, i
 
         flag = 0;
 
-        if (state * 4ULL > 0xFF || i >= size)
+        if ((uint64_t)state > 0xFF / 4 || i >= size)
             continue;
 
         pfx = ((state + 8) >> 5) + (state ? ff_clz(state): 32) - 24;