cgroup: annotate cgroup_init_subsys with __init

It is called by cgroup_init() and cgroup_init_early() only, which are
annotated with __init.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/cgroup.c

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index bd6122c..97ab04c 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2444,7 +2444,7 @@
 	return 0;
 }
 
-static void cgroup_init_subsys(struct cgroup_subsys *ss)
+static void __init cgroup_init_subsys(struct cgroup_subsys *ss)
 {
 	struct cgroup_subsys_state *css;
 	struct list_head *l;