cpufreq: cpu-boost: Introduce scheduler assisted load based syncs

Previously, on getting a migration notification cpu-boost changed
the scaling min of the destination frequency to match that of the
source frequency or sync_threshold whichever was minimum.

If the scheduler migration notification is extended with task load
(cpu demand) information, the cpu boost driver can use this load to
compute a suitable frequency for the migrating task. The required
frequency for the task is calculated by taking the load percentage
of the max frequency and no sync is performed if the load is less
than a particular value (migration_load_threshold).This change is
beneficial for both perf and power as demand of a task is taken into
consideration while making cpufreq decisions and unnecessary syncs
for lightweight tasks are avoided.

The task load information provided by scheduler comes from a
window-based load collection mechanism which also normalizes the
load collected by the scheduler to the max possible frequency
across all CPUs.

Change-Id: Id2ba91cc4139c90602557f9b3801fb06b3c38992
Signed-off-by: Rohit Gupta <rohgup@codeaurora.org>
cpufreq: cpu-boost: Handle wakeup hints received for foreground tasks

A previous change modifies the notification conditions in the scheduler
to call the notifier chain even on foreground_thread wakeups for tasks
having load more than a threshold value.

If load_based_syncs is turned OFF then we do not need to perform
cpu boost for wakeup hints for foreground tasks from scheduler

Change-Id: Ifbdd3eccac5c9892dfc3a3c3edbfc0df766478ed
Signed-off-by: Rohit Gupta <rohgup@codeaurora.org>