Use 6STACK_DIG for the AD2000BX variant of the AD1989B chip used by Asus
on their Asus P5Q Premium and Pro boards.
Signed-off-by: Robin H. Johnson <robbat2@gentoo.org> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Jaroslav Kysela <perex@perex.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>