sched: Add feature 'UTIL_TASKGROUP' for dynamic affinity

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I526XC



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If the feature enabled, util_avg of bottom-level tg is used,
otherwise, util_avg of rq's cfs_rq is used.

Signed-off-by: Hui Tang <tanghui20@huawei.com>