[ALSA] Fix compile warnings in ak4xxx-adda.c

Fixed compile warnings in ak4xxx-adda.c reagarding missing
enum cases in switch.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>
diff --git a/sound/i2c/other/ak4xxx-adda.c b/sound/i2c/other/ak4xxx-adda.c
index d76d8b0..0aea536 100644
--- a/sound/i2c/other/ak4xxx-adda.c
+++ b/sound/i2c/other/ak4xxx-adda.c
@@ -137,6 +137,8 @@
 	case SND_AK4381:
 		ak4381_reset(ak, state);
 		break;
+	default:
+		break;
 	}
 }
 
@@ -727,6 +729,9 @@
 		case SND_AK4381:
 			ctl->private_value = AK_COMPOSE(idx, 1, 1, 0);
 			break;
+		default:
+			err = -EINVAL;
+			goto __error;
 		}
 		ctl->private_data = ak;
 		err = snd_ctl_add(ak->card,