[ALSA] snd-powermac: no longer handle anything with a layout-id property

This patch removes from snd-powermac the code that check for the layout-id
and instead adds code that makes it refuse loading when a layout-id property
is present, nothing that snd-aoa should be used.
It also removes the 'toonie' codec from snd-powermac which was only ever
used on the mac mini which has a layout-id property.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Takashi Iwai <tiwai@suse.de>