!7971 fbmon: prevent division by zero in fb_videomode_from_videomode()

Merge Pull Request from: @ci-robot 
 
PR sync from: Hui Tang <tanghui20@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/LSYYIAS3XQ2NZMTOG4X5N6KZK74WH37J/ 
 
https://gitee.com/src-openeuler/kernel/issues/I9QGIW 
 
Link:https://gitee.com/openeuler/kernel/pulls/7971

 

Reviewed-by: Jialin Zhang <zhangjialin11@huawei.com>
Reviewed-by: Liu YongQiang <liuyongqiang13@huawei.com>
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>
Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>