ARM: tegra: power: Use runnable threads average for hotplug

Sample scheduler runnable threads average in auto-hotplug work
function and use it to determine the auto-hotplug target for number
of on-line cores. Use cpu up delay as sampling period, and enforce
down delay by checking last cpu configuration change time stamp.

Bug 958978

Change-Id: I4280a11d39914687e6ffaa6f38df594d10aedaa9
Signed-off-by: Alex Frid <afrid@nvidia.com>
(cherry picked from commit 507e2ef5e4f09b23de2e924003dba259d3c8bc3c)
Reviewed-on: http://git-master/r/111638
Reviewed-by: Sai Gurrappadi <sgurrappadi@nvidia.com>
Tested-by: Sai Gurrappadi <sgurrappadi@nvidia.com>
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Peter Boonstoppel <pboonstoppel@nvidia.com>
Reviewed-by: Yu-Huan Hsu <yhsu@nvidia.com>

Conflicts:
	arch/arm/mach-tegra/cpu-tegra3.c
arm: tegra: hotplug: tune runnable thread params.

Tuned the runnable threads threshold from 5/9/13 to 5/9/10 in order to improve performance

Bug 958978

Change-Id: I77abcd0077845517f2b5f7487c547f8a5157c2c7
Signed-off-by: Wen Yi <wyi@nvidia.com>
(cherry picked from commit 25a97f57661353fbb5ee40faed296befbf635178)
Reviewed-on: http://git-master/r/111639
Reviewed-by: Sai Gurrappadi <sgurrappadi@nvidia.com>
Tested-by: Sai Gurrappadi <sgurrappadi@nvidia.com>
Reviewed-by: Peter Boonstoppel <pboonstoppel@nvidia.com>
Reviewed-by: Yu-Huan Hsu <yhsu@nvidia.com>