!3022 fs/dirty_pages: fix some errors in seq_read_dirty()

Merge Pull Request from: @ci-robot 
 
PR sync from: Zizhi Wo <wozizhi@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/5GBJUVYDS6NTIEFF6IEWIAAZNOL4QJO7/ 
 
https://gitee.com/openeuler/kernel/issues/I8JUUC?from=project-issue 
 
Link:https://gitee.com/openeuler/kernel/pulls/3022

 

Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: zhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>