[ALSA] Remove nested mutexes in seq_ports.c

Removed nested mutexes in the removal routine of port connections.
The port is guaranteed to be offline before calling it, so no mutex
is needed.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/core/seq/seq_ports.c b/sound/core/seq/seq_ports.c
index 5f46ee9..334579a9 100644
--- a/sound/core/seq/seq_ports.c
+++ b/sound/core/seq/seq_ports.c
@@ -221,7 +221,6 @@
 {
 	struct list_head *p, *n;
 
-	down_write(&grp->list_mutex);
 	list_for_each_safe(p, n, &grp->list_head) {
 		struct snd_seq_subscribers *subs;
 		struct snd_seq_client *c;
@@ -259,7 +258,6 @@
 			snd_seq_client_unlock(c);
 		}
 	}
-	up_write(&grp->list_mutex);
 }
 
 /* delete port data */