ARM: Tegra: Added support to run at two frequency modes

CPU clock is now capped at an normal frequency that is below
its maximum and allowed to run at a high frequency
only once within a period of time. By default the delay is set to
5*DOWN_DELAY, allowing a maximum of 20% high frequency time.

Sysfs knobs were also added that allows userspace tuning

Bug 1003531

Change-Id: Ic9be46cdae099771950f14e8a6ca79eeab7adbba
Signed-off-by: Xiao Bo Zhao <xiaoboz@nvidia.com>
(cherry picked from commit 779a488fb850eb452a7b43788b87edb4186b69b9)
Reviewed-on: http://git-master/r/121042
Reviewed-by: Ryan Wong <ryanw@nvidia.com>
Reviewed-by: Automatic_Commit_Validation_User