ALSA: bebob: Correction for return value of special_clk_ctl_put() in error

This commit is a supplement to my previous patch.
http://mailman.alsa-project.org/pipermail/alsa-devel/2014-July/079190.html

The special_clk_ctl_put() still returns 0 in error handling case. It should
return -EINVAL.
Signed-off-by: NTakashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

sound/firewire/bebob/bebob_maudio.c

@@ -381,7 +381,7 @@ static int special_clk_ctl_put(struct snd_kcontrol *kctl,
 
 	id = uval->value.enumerated.item[0];
 	if (id >= ARRAY_SIZE(special_clk_labels))
-		return 0;
+		return -EINVAL;
 
 	mutex_lock(&bebob->mutex);