avformat/iamf_parse: Check for 0 samples

Fixes: division by zero
Fixes: 70561/clusterfuzz-testcase-minimized-ffmpeg_IO_DEMUXER_fuzzer-6199435013455872
Fixes: 70565/clusterfuzz-testcase-minimized-ffmpeg_dem_MOV_fuzzer-5783790316748800

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

libavformat/iamf_parse.c

@@ -252,7 +252,7 @@ static int codec_config_obu(void *s, IAMFContext *c, AVIOContext *pb, int len)
     if (ret < 0)
         goto fail;
 
-    if ((codec_config->nb_samples > INT_MAX) ||
+    if ((codec_config->nb_samples > INT_MAX) || codec_config->nb_samples <= 0 ||
         (-codec_config->audio_roll_distance > INT_MAX / codec_config->nb_samples)) {
         ret = AVERROR_INVALIDDATA;
         goto fail;