avformat/movenc: Write version 2 of audio atom if channels is not known

The version 1 needs the channel count and would divide by 0
Fixes: division by 0
Fixes: fpe_movenc.c_1108_1.ogg
Fixes: fpe_movenc.c_1108_2.ogg
Fixes: fpe_movenc.c_1108_3.wav

Found-by: #CHEN HONGXU# <HCHEN017@e.ntu.edu.sg>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
static int mov_write_dref_tag(AVIOContext *pb)
{
    avio_wb32(pb, 28); /* size */
    ffio_wfourcc(pb, "dref");
    avio_wb32(pb, 0); /* version & flags */
    avio_wb32(pb, 1); /* entry count */

    avio_wb32(pb, 0xc); /* size */
    ffio_wfourcc(pb, "url ");
    avio_wb32(pb, 1); /* version & flags */

    return 28;
}

static int mov_write_dref_tag(AVIOContext *pb)
{
    avio_wb32(pb, 28); /* size */
    ffio_wfourcc(pb, "dref");
    avio_wb32(pb, 0); /* version & flags */
    avio_wb32(pb, 1); /* entry count */

    avio_wb32(pb, 0xc); /* size */
    ffio_wfourcc(pb, "url ");
    avio_wb32(pb, 1); /* version & flags */

    return 28;
}
