ALSA: bebob: Fix a missing to unlock mutex in error handling case

In error handling case, special_clk_ctl_put() returns without unlock_mutex(),
therefore the mutex is still locked. This commit moves mutex_lock() after
the error handling case.

This commit is my solution for this post.

[PATCH -next] ALSA: bebob: Fix missing unlock on error in special_clk_ctl_put()
https://lkml.org/lkml/2014/7/20/12

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/firewire/bebob/bebob_maudio.c

@@ -379,12 +379,12 @@ static int special_clk_ctl_put(struct snd_kcontrol *kctl,
 	struct special_params *params = bebob->maudio_special_quirk;
 	int err, id;
 
-	mutex_lock(&bebob->mutex);
-
 	id = uval->value.enumerated.item[0];
 	if (id >= ARRAY_SIZE(special_clk_labels))
 		return 0;
 
+	mutex_lock(&bebob->mutex);
+
 	err = avc_maudio_set_special_clk(bebob, id,
 					 params->dig_in_fmt,
 					 params->dig_out_fmt,