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_vmhd_tag(AVIOContext *pb)
{
    avio_wb32(pb, 0x14); /* size (always 0x14) */
    ffio_wfourcc(pb, "vmhd");
    avio_wb32(pb, 0x01); /* version & flags */
    avio_wb64(pb, 0); /* reserved (graphics mode = copy) */
    return 0x14;
}

static int mov_write_vmhd_tag(AVIOContext *pb)
{
    avio_wb32(pb, 0x14); /* size (always 0x14) */
    ffio_wfourcc(pb, "vmhd");
    avio_wb32(pb, 0x01); /* version & flags */
    avio_wb64(pb, 0); /* reserved (graphics mode = copy) */
    return 0x14;
}
