avformat/matroskadec: check generic audio deinterleaver sub_packet_size against frame_size

Fixes use of uninitialized memory
Fixes: msan_uninit-mem_7f67d052a530_7517_nosound.mkv
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/matroskadec.c

@@ -2181,7 +2181,7 @@ static int matroska_parse_rm_audio(MatroskaDemuxContext *matroska,
             }
             memcpy(track->audio.buf + y*w, data, w);
         } else {
-            if (size < sps * w / sps || h<=0) {
+            if (size < sps * w / sps || h<=0 || w%sps) {
                 av_log(matroska->ctx, AV_LOG_ERROR,
                        "Corrupt generic RM-style audio packet size\n");
                 return AVERROR_INVALIDDATA;