!1660 remove cpu.qos_leve from root cpu cgroup

Merge Pull Request from: @zhangwei123171 
 


/sys/fs/cgroup/cpu/cpu.qos_level is not needed, and easy to cause misunderstanding. 
 
Link:https://gitee.com/openeuler/kernel/pulls/1660

 

Reviewed-by: zhao xiaoqiang <zhaoxiaoqiang11@jd.com>
Reviewed-by: Zucheng Zheng <zhengzucheng@huawei.com>
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>
Acked-by: Xie XiuQi <xiexiuqi@huawei.com>