cpuset: fix the WARN_ON() in update_nodemasks_hier()

The WARN_ON() is used to check if we break the legal hierarchy, on
which the effective mems should be equal to configured mems.
Reported-by: Mike Qiu <qiudayu@linux.vnet.ibm.com>
Tested-by: Mike Qiu <qiudayu@linux.vnet.ibm.com>
Signed-off-by: Li Zefan <lizefan@huawei.com>

kernel/cpuset.c

@@ -1136,7 +1136,7 @@ static void update_nodemasks_hier(struct cpuset *cs, nodemask_t *new_mems)
 		mutex_unlock(&callback_mutex);
 
 		WARN_ON(!cgroup_on_dfl(cp->css.cgroup) &&
-			nodes_equal(cp->mems_allowed, cp->effective_mems));
+			!nodes_equal(cp->mems_allowed, cp->effective_mems));
 
 		update_tasks_nodemask(cp);