Revert "sched: Periodically decay max cost of idle balance"

This reverts commit 47d3bbe138e1969f59db7f196f477551292e8884.
Revert "sched: Consider max cost of idle balance per sched domain"

This reverts commit d4348c2a490cafa7104ad2e0bc871ae49ec6f5cf.
Revert "sched: Reduce overestimating rq->avg_idle"

This reverts commit 645d24f8255285abda0056bb0f06782b470fe6bf.