!3935 pid_ns: Make pid_max per namespace

Merge Pull Request from: @ci-robot 
 
PR sync from: Yi Yang <yiyang13@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/ZV4MFUHGQKKQQYAHMCUHF5XTWC7JUZ6Q/ 
 
https://gitee.com/openeuler/kernel/issues/I8TCPY 
 
Link:https://gitee.com/openeuler/kernel/pulls/3935

 

Reviewed-by: Lu Jialin <lujialin4@huawei.com>
Reviewed-by: zhangyi (F) <yi.zhang@huawei.com>
Reviewed-by: Zucheng Zheng <zhengzucheng@huawei.com>
Reviewed-by: Zhang Jianhua <chris.zjh@huawei.com>
Reviewed-by: Liu Chao <liuchao173@huawei.com>
Reviewed-by: Xu Kuohai <xukuohai@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>