fs/ufs: restore s_lock mutex_init()

Add last missing line in commit "cdd9eefdf905"
("fs/ufs: restore s_lock mutex")

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/ufs/super.c b/fs/ufs/super.c
index afe9955..dc33f94 100644
--- a/fs/ufs/super.c
+++ b/fs/ufs/super.c
@@ -801,6 +801,7 @@
 	UFSD("flag %u\n", (int)(sb->s_flags & MS_RDONLY));
 	
 	mutex_init(&sbi->mutex);
+	mutex_init(&sbi->s_lock);
 	spin_lock_init(&sbi->work_lock);
 	INIT_DELAYED_WORK(&sbi->sync_work, delayed_sync_fs);
 	/*