usb: host: tegra: boost cpu frequency when bus is active

usb: host: tegra: boost cpu frequency when bus is active

Boost cpu frequency (based upon TEGRA_EHCI_BOOST_CPU_FREQ)
when the usb bus is active and remove the boost when usb
bus is suspended.

Bug 1266414

Change-Id: Ic5b7b1ecc923caf7da458383112ed0e647448a57
Signed-off-by: Rohith Seelaboyina <rseelaboyina@nvidia.com>
Reviewed-on: http://git-master/r/226914
(cherry picked from commit 85c49d81cd5c6760567a44878fedbc09c422841d)
Reviewed-on: http://git-master/r/227803
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Venkat Moganty <vmoganty@nvidia.com>