initialize namespace_sem statically

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/namespace.c

@@ -39,7 +39,7 @@ static int mnt_group_start = 1;
 static struct list_head *mount_hashtable __read_mostly;
 static struct list_head *mountpoint_hashtable __read_mostly;
 static struct kmem_cache *mnt_cache __read_mostly;
-static struct rw_semaphore namespace_sem;
+static DECLARE_RWSEM(namespace_sem);
 
 /* /sys/fs */
 struct kobject *fs_kobj;
@@ -2767,8 +2767,6 @@ void __init mnt_init(void)
 	unsigned u;
 	int err;
 
-	init_rwsem(&namespace_sem);
-
 	mnt_cache = kmem_cache_create("mnt_cache", sizeof(struct mount),
 			0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);