avcodec/wmalosslessdec: Check that padding bits is not more than sample bits

Fixes: left shift of 1 by 31 places cannot be represented in type 'int'
Fixes: 18817/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WMALOSSLESS_fuzzer-5713317180211200

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

libavcodec/wmalosslessdec.c

@@ -950,6 +950,8 @@ static int decode_subframe(WmallDecodeCtx *s)
             for (j = 0; j < subframe_len; j++)
                 s->channel_residues[i][j] = get_sbits_long(&s->gb, bits);
     } else {
+        if (s->bits_per_sample < padding_zeroes)
+            return AVERROR_INVALIDDATA;
         for (i = 0; i < s->num_channels; i++) {
             if (s->is_channel_coded[i]) {
                 decode_channel_residues(s, i, subframe_len);