ALSA: hda - Force AD1988_6STACK_DIG for Asus M3N-HT Deluxe

The microphone input on the back panel (pink connector)
stopped operating correctly after an upgrade from
2.6.35 to 2.6.38; the actual problem manifests itself
as a lack of microphone bias voltage (VREF_HIZ) on
node 0x17.
With AD1988_6STACK_DIG the maximum bias voltage (VREF_80)
is applied and the headset operates correctly.
Signed-off-by: Tony Vroon <tony@linx.net>
Tested-by: Doug Redlich <pbrigade@nxltech.net>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/hda/patch_analog.c

@@ -3159,6 +3159,7 @@ static const struct snd_pci_quirk ad1988_cfg_tbl[] = {
 	SND_PCI_QUIRK(0x1043, 0x81ec, "Asus P5B-DLX", AD1988_6STACK_DIG),
 	SND_PCI_QUIRK(0x1043, 0x81f6, "Asus M2N-SLI", AD1988_6STACK_DIG),
 	SND_PCI_QUIRK(0x1043, 0x8277, "Asus P5K-E/WIFI-AP", AD1988_6STACK_DIG),
+	SND_PCI_QUIRK(0x1043, 0x82c0, "Asus M3N-HT Deluxe", AD1988_6STACK_DIG),
 	SND_PCI_QUIRK(0x1043, 0x8311, "Asus P5Q-Premium/Pro", AD1988_6STACK_DIG),
 	{}
 };