cpufreq: interactive: Add support for using scheduler inputs

Interactive governor does not have enough information about the tasks
on a CPU to make a more informed decision on the frequency the CPUs
should run at. To address this problem, modify interactive governor
to get load information from scheduler. In addition, it can get
notification from scheduler on significant load change to reevaluate
CPU frequency immediately.

Add two sysfs file to control the behavior of load evaluation:
use_sched_load:
	When enabled, governor uses load information from scheduler
	instead of busy/idle time from past window.
use_migration_notif:
	Whenever a task migrates, scheduler might send a notification
	so that governor can re-evaluate load and scale frequency.
	Governor will ignore this notification unless both
	use_sched_hint 	and use_migration_notification are true for
	the policy group.

Change-Id: Iaf66e424c6166ec15480db027002b3a3b357d79c
Signed-off-by: Junjie Wu <junjiew@codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>