[ALSA] atiixp - Add a parameter ac97_quirk

Add an option to specify the AC'97 codec instead of
probing.  This is a fix for bugzilla #7467.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>