!2550 xen/events: replace evtchn_rwlock with RCU

Merge Pull Request from: @ci-robot 
 
PR sync from: Liu Shixin <liushixin2@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/44476T7OYFUEKSAOUT4NZMHIJ3V7RZDV/ 
 
https://gitee.com/src-openeuler/kernel/issues/I896EC 
 
Link:https://gitee.com/openeuler/kernel/pulls/2550

 

Reviewed-by: Liu YongQiang <liuyongqiang13@huawei.com>
Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>