[ALSA] hda: fix STAC927x power management

Fix issue on STAC927x codecs that first DAC was getting powered down
even if was being used.
Signed-off-by: Matthew Ranostay <mranostay@embeddedalley.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/hda/patch_sigmatel.c

@@ -2893,7 +2893,8 @@ static void stac92xx_power_down(struct hda_codec *codec)
 	/* power down inactive DACs */
 	hda_nid_t *dac;
 	for (dac = spec->dac_list; *dac; dac++)
-		if (!is_in_dac_nids(spec, *dac))
+		if (!is_in_dac_nids(spec, *dac) &&
+			spec->multiout.hp_nid != *dac)
 			snd_hda_codec_write_cache(codec, *dac, 0,
 					AC_VERB_SET_POWER_STATE, AC_PWRST_D3);
 }