avcodec/notchlc: Check bytes left before reading

Fixes: Use of uninitialized value
Fixes: 71230/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_NOTCHLC_fuzzer-4624502095413248

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

libavcodec/notchlc.c

@@ -93,6 +93,9 @@ static int lz4_decompress(AVCodecContext *avctx,
             } while (current == 255);
         }
 
+        if (bytestream2_get_bytes_left(gb) < num_literals)
+            return AVERROR_INVALIDDATA;
+
         if (pos + num_literals < HISTORY_SIZE) {
             bytestream2_get_buffer(gb, history + pos, num_literals);
             pos += num_literals;