hulk inclusion
category: feature
bugzilla: 51827
CVE: NA

--------------------------------------

Fix it by moving memcg_priority from struct mem_cgroup to
struct mem_cgroup_extension.
Signed-off-by: NJing Xiangfeng <jingxiangfeng@huawei.com>
Reviewed-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>