ALSA: HDA: Fixup unnecessary volume control index on Realtek ALC88x

Without this change, a volume control named "Surround" or "Side" would
get an unnecessary index, causing it to be ignored by the vmaster and
PulseAudio.
Tested-by: NBartłomiej Żogała <nusch88@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: NDavid Henningsson <david.henningsson@canonical.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

sound/pci/hda/patch_realtek.c

@@ -5136,16 +5136,19 @@ static int alc880_auto_create_multi_out_ctls(struct alc_spec *spec,
 				return err;
 		} else {
 			const char *name = pfx;
-			if (!name)
+			int index = i;
+			if (!name) {
 				name = chname[i];
+				index = 0;
+			}
 			err = __add_pb_vol_ctrl(spec, ALC_CTL_WIDGET_VOL,
-						name, i,
+						name, index,
 					  HDA_COMPOSE_AMP_VAL(nid, 3, 0,
 							      HDA_OUTPUT));
 			if (err < 0)
 				return err;
 			err = __add_pb_sw_ctrl(spec, ALC_CTL_BIND_MUTE,
-					       name, i,
+					       name, index,
 					  HDA_COMPOSE_AMP_VAL(nid, 3, 2,
 							      HDA_INPUT));
 			if (err < 0)