[ALSA] create driver symlink in snd-aoa /sys/bus/aoa-soundbus/devices/*/

create sysfs driver symlink for snd-aoa in /sys/bus/aoa-soundbus/devices/*/
Acked-by: Johannes Berg <johannes@sipsolutions.net>

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>