ALSA: gus: add a check of the status of snd_ctl_add

snd_ctl_add() could fail, so let's check its status and issue an error
message if it indeed fails.
Signed-off-by: Kangjie Lu <kjlu@umn.edu>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/isa/gus/gus_main.c

@@ -92,8 +92,17 @@ static const struct snd_kcontrol_new snd_gus_joystick_control = {
 
 static void snd_gus_init_control(struct snd_gus_card *gus)
 {
-	if (!gus->ace_flag)
-		snd_ctl_add(gus->card, snd_ctl_new1(&snd_gus_joystick_control, gus));
+	int ret;
+
+	if (!gus->ace_flag) {
+		ret =
+			snd_ctl_add(gus->card,
+					snd_ctl_new1(&snd_gus_joystick_control,
+						gus));
+		if (ret)
+			snd_printk(KERN_ERR "gus: snd_ctl_add failed: %d\n",
+					ret);
+	}
 }
 
 /*