au: switch to ff_pcm_read_packet() again, after the merge

This fixes G722 durations

Suggested-by: durandal_1707
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/au.c

@@ -135,27 +135,12 @@ static int au_read_header(AVFormatContext *s)
     return 0;
 }
 
-static int au_read_packet(AVFormatContext *s, AVPacket *pkt)
-{
-    int ret;
-
-    ret = av_get_packet(s->pb, pkt, BLOCK_SIZE *
-                        s->streams[0]->codec->block_align);
-    if (ret < 0)
-        return ret;
-
-    pkt->stream_index = 0;
-    pkt->duration     = ret / s->streams[0]->codec->block_align;
-
-    return 0;
-}
-
 AVInputFormat ff_au_demuxer = {
     .name        = "au",
     .long_name   = NULL_IF_CONFIG_SMALL("Sun AU"),
     .read_probe  = au_probe,
     .read_header = au_read_header,
-    .read_packet = au_read_packet,
+    .read_packet = ff_pcm_read_packet,
     .read_seek   = ff_pcm_read_seek,
     .codec_tag   = (const AVCodecTag* const []) { codec_au_tags, 0 },
 };