migration: Use vmstate_register_any() for audio

We can have more than one audio backend.

void audio_init_audiodevs(void)
{
    AudiodevListEntry *e;

    QSIMPLEQ_FOREACH(e, &audiodevs, next) {
        audio_init(e->dev, &error_fatal);
    }
}

Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231020090731.28701-12-quintela@redhat.com>

audio/audio.c

@@ -1781,7 +1781,7 @@ static AudioState *audio_init(Audiodev *dev, Error **errp)
 
     QTAILQ_INSERT_TAIL(&audio_states, s, list);
     QLIST_INIT (&s->card_head);
-    vmstate_register (NULL, 0, &vmstate_audio, s);
+    vmstate_register_any(NULL, &vmstate_audio, s);
     return s;
 
 out: