!6659 sched/rt: Fix sysctl_sched_rr_timeslice intial value

Merge Pull Request from: @ci-robot 
 
PR sync from: Cheng Yu <serein.chengyu@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/554B45VHNBPPSKYPLR7IDGF64IEXQDOL/ 
 
https://gitee.com/openeuler/kernel/issues/I9K34B 
 
Link:https://gitee.com/openeuler/kernel/pulls/6659

 

Reviewed-by: Liu YongQiang <liuyongqiang13@huawei.com>
Reviewed-by: Zucheng Zheng <zhengzucheng@huawei.com>
Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>