!3376 mm/mempolicy: check preferred_node rather than nodes for MPOL_PREFERRED

Merge Pull Request from: @ci-robot 
 
PR sync from: Wupeng Ma <mawupeng1@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/THH4KNGEOU4JJUCIHSS4BGAPHUJ7HUZ3/ 
 
https://gitee.com/openeuler/kernel/issues/I8O41A 
 
Link:https://gitee.com/openeuler/kernel/pulls/3376

 

Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>