avformat/avr: Check sample rate

Fixes: 54979/clusterfuzz-testcase-minimized-ffmpeg_dem_AVR_fuzzer-6681035461230592
Fixes: Timeout

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

libavformat/avr.c

@@ -70,6 +70,9 @@ static int avr_read_header(AVFormatContext *s)
     avio_skip(s->pb, 1); // replay speed
 
     st->codecpar->sample_rate = avio_rb24(s->pb);
+    if (st->codecpar->sample_rate == 0)
+        return AVERROR_INVALIDDATA;
+
     avio_skip(s->pb, 4 * 3);
     avio_skip(s->pb, 2 * 3);
     avio_skip(s->pb, 20);