ALSA: HDA: Fix internal microphone on Dell Studio 16 XPS 1645

commit ffe535ed upstream.

More than one user reports that changing the model from "both" to
"dmic" makes their Internal Mic work.
Tested-by: Martin Ling <martin-launchpad@earth.li>
BugLink: https://bugs.launchpad.net/bugs/795823Signed-off-by: David Henningsson <david.henningsson@canonical.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

sound/pci/hda/patch_sigmatel.c

@@ -1631,7 +1631,7 @@ static const struct snd_pci_quirk stac92hd73xx_cfg_tbl[] = {
 	SND_PCI_QUIRK(PCI_VENDOR_ID_DELL, 0x02bd,
 				"Dell Studio 1557", STAC_DELL_M6_DMIC),
 	SND_PCI_QUIRK(PCI_VENDOR_ID_DELL, 0x02fe,
-				"Dell Studio XPS 1645", STAC_DELL_M6_BOTH),
+				"Dell Studio XPS 1645", STAC_DELL_M6_DMIC),
 	SND_PCI_QUIRK(PCI_VENDOR_ID_DELL, 0x0413,
 				"Dell Studio 1558", STAC_DELL_M6_DMIC),
 	{} /* terminator */