Added the support for Gigabyte S-Series GA-M57SLI-S4 motherboard
(model=6stack-dig).
Signed-off-by: NTobin Davis <tdavis@dsl-only.net>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NJaroslav Kysela <perex@suse.cz>