cgroup: move list add after list head initilization

2243076ad1 ("cgroup: initialize cgrp->allcg_node in
init_cgroup_housekeeping()") initializes cgrp->allcg_node in
init_cgroup_housekeeping().  Then in init_cgroup_root(), we should
call init_cgroup_housekeeping() before adding it to &root->allcg_list;
otherwise, we are initializing an entry already in a list.

Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 55a0a77..c02b055 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1401,8 +1401,8 @@
 	root->number_of_cgroups = 1;
 	cgrp->root = root;
 	cgrp->top_cgroup = cgrp;
-	list_add_tail(&cgrp->allcg_node, &root->allcg_list);
 	init_cgroup_housekeeping(cgrp);
+	list_add_tail(&cgrp->allcg_node, &root->allcg_list);
 }
 
 static bool init_root_id(struct cgroupfs_root *root)