!2319 add a mutex lock for qos_level

Merge Pull Request from: @zhangwei123171 
 


 In order to reduce the concurrent operations introduced
    by users setting qos_level, we add a mutex lock.

 
 
Link:https://gitee.com/openeuler/kernel/pulls/2319

 

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