sched/fair: ignore the rt or dl task in tg_change_scheduler

jingdong inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7S71H



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When switching the sched policy of the container process
through qos_level, you need to ignore the rt or dl task.

Both online task and offline task are limited to the
cfs scheduling class.

Fixes: bda15404 ("sched: Introduce qos scheduler for co-location")
Signed-off-by: zhangwei123171 <zhangwei123171@jd.com>
Reviewed-by: zhaoxiaoqiang11 <zhaoxiaoqiang11@jd.com>