!4702 efivarfs: force RO when remounting if SetVariable is not supported

Merge Pull Request from: @ci-robot 
 
PR sync from: Zhihao Cheng <chengzhihao1@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/EOYIAGJDU3XWUK5Z4GO7463OVQH6G3YQ/ 
 
https://gitee.com/src-openeuler/kernel/issues/I93EC7 
 
Link:https://gitee.com/openeuler/kernel/pulls/4702

 

Reviewed-by: zhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>