sched/qos: Add qos_tg_{throttle,unthrottle}_{up,down}

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4VZJT


CVE: NA

--------------------------------

1. Qos throttle reuse tg_{throttle,unthrottle}_{up,down} that
can write some cfs-bandwidth fields, it may cause some unknown
data error. So add qos_tg_{throttle,unthrottle}_{up,down} for
qos throttle.

2. walk_tg_tree_from() caller must hold rcu_lock, currently there is
none, so add it now.

Signed-off-by: Zhang Qiao <zhangqiao22@huawei.com>
Reviewed-by: Chen Hui <judy.chenhui@huawei.com>
Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>