[ALSA] [snd-hda-intel] fix sound on some Asus W6A chips

This patch adds support in ALSA snd-hda-intel driver for Asus W6A
motherboard as reported in MDV Bugzilla #19962
(see http://qa.mandriva.com/show_bug.cgi?id=19962

)

Signed-off-by: Danny Tholen <danny@mailmij.org>
Signed-off-by: Thomas Backlund <tmb@mandriva.org>
Signed-off-by: Thierry Vignaud <tvignaud@mandriva.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>