ALSA: hda - Add a workaround for ASUS A7K

ASUS A7K needs additional GPIO1 bit setup; it has to be cleared.
Added a new fixup hook for this laptop so that it works as is.

Refernece: Novell bnc#494309
	http://bugzilla.novell.com/show_bug.cgi?id=494309

Signed-off-by: Takashi Iwai <tiwai@suse.de>