!1374 etmem: fix the div 0 problem in swapcache reclaim process

Merge Pull Request from: @ci-robot 
 
PR sync from: liubo <liubo254@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/ZQ7VFVIBVFWTAG7WEO5ZIGMIIEHJTPHW/ 
 
 
Link:https://gitee.com/openeuler/kernel/pulls/1374

 

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