avcodec/pcm-dvd: reset last header on errors

Fixes: msan_uninit-mem_7f4fff975a2c_4957_dvd_audio_sample.aob
Fixes use of uninitialized memory
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/pcm-dvd.c

@@ -70,6 +70,7 @@ static int pcm_dvd_parse_header(AVCodecContext *avctx, const uint8_t *header)
     /* early exit if the header didn't change apart from the frame number */
     if (s->last_header == header_int)
         return 0;
+    s->last_header = -1;
 
     if (avctx->debug & FF_DEBUG_PICT_INFO)
         av_dlog(avctx, "pcm_dvd_parse_header: header = %02x%02x%02x\n",