[ALSA] hda-codec: Add 4 channel support for Realtek ALC883

I had a request for a 4 channel mode.  This should implement front
and surround outputs, leaving the 3rd plug for mic input.
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>

sound/pci/hda/patch_realtek.c

@@ -6086,6 +6086,18 @@ static struct hda_verb alc883_3ST_ch2_init[] = {
 	{ } /* end */
 };
 
+/*
+ * 4ch mode
+ */
+static struct hda_verb alc883_3ST_ch4_init[] = {
+	{ 0x18, AC_VERB_SET_PIN_WIDGET_CONTROL, PIN_VREF80 },
+	{ 0x18, AC_VERB_SET_AMP_GAIN_MUTE, AMP_OUT_MUTE },
+	{ 0x1a, AC_VERB_SET_PIN_WIDGET_CONTROL, PIN_OUT },
+	{ 0x1a, AC_VERB_SET_AMP_GAIN_MUTE, AMP_OUT_UNMUTE },
+	{ 0x1a, AC_VERB_SET_CONNECT_SEL, 0x01 },
+	{ } /* end */
+};
+
 /*
  * 6ch mode
  */
@@ -6099,8 +6111,9 @@ static struct hda_verb alc883_3ST_ch6_init[] = {
 	{ } /* end */
 };
 
-static struct hda_channel_mode alc883_3ST_6ch_modes[2] = {
+static struct hda_channel_mode alc883_3ST_6ch_modes[3] = {
 	{ 2, alc883_3ST_ch2_init },
+	{ 4, alc883_3ST_ch4_init },
 	{ 6, alc883_3ST_ch6_init },
 };