ALSA: pcm_oss, fix locking typo

s/mutex_lock/mutex_unlock/ on 2 fail paths in snd_pcm_oss_proc_write.
Probably a typo, lock should be unlocked when leaving the function.
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/core/oss/pcm_oss.c

@@ -2872,7 +2872,7 @@ static void snd_pcm_oss_proc_write(struct snd_info_entry *entry,
 			setup = kmalloc(sizeof(*setup), GFP_KERNEL);
 			if (! setup) {
 				buffer->error = -ENOMEM;
-				mutex_lock(&pstr->oss.setup_mutex);
+				mutex_unlock(&pstr->oss.setup_mutex);
 				return;
 			}
 			if (pstr->oss.setup_list == NULL)
@@ -2886,7 +2886,7 @@ static void snd_pcm_oss_proc_write(struct snd_info_entry *entry,
 			if (! template.task_name) {
 				kfree(setup);
 				buffer->error = -ENOMEM;
-				mutex_lock(&pstr->oss.setup_mutex);
+				mutex_unlock(&pstr->oss.setup_mutex);
 				return;
 			}
 		}