ALSA: hda/realtek - Set pcbeep amp for ALC668

Set the missing pcbeep default amp for ALC668.

Signed-off-by: Kailang Yang <kailang@realtek.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/hda/patch_realtek.c b/sound/pci/hda/patch_realtek.c
index 60973fd..c4ad9d1 100644
--- a/sound/pci/hda/patch_realtek.c
+++ b/sound/pci/hda/patch_realtek.c
@@ -5118,6 +5118,7 @@
 		case 0x10ec0272:
 		case 0x10ec0663:
 		case 0x10ec0665:
+		case 0x10ec0668:
 			set_beep_amp(spec, 0x0b, 0x04, HDA_INPUT);
 			break;
 		case 0x10ec0273: