power: Add CPU boosting interface

 * Boosts CPU using Power HAL for the given duration.
 * Duration is given in microseconds.
 * Power HAL must implement POWER_HINT_CPU_BOOST.

Change-Id: Ic79baf7e3d0f75483c2fe8a242b4c3d93368b68b

Conflicts:
	services/jni/com_android_server_power_PowerManagerService.cpp

Change-Id: Ic79baf7e3d0f75483c2fe8a242b4c3d93368b68b

Conflicts:
	core/java/android/os/IPowerManager.aidl
PowerManagerService: Implement setButtonBrightnessOverrideFromWindowManager method

Differs from Android 4.1 (and earlier) implementation in that the
overridden button light still turns off after BUTTON_ON_DURATION instead of
staying on until screen off.  However, button lights are annoying, and
really the purpose of this is to allow apps (e.g., Screen Filter) to
_disable_ the button lights altogether.

Change-Id: If0639dbe01134b72b05fee7f8cd9368dc9a71e4f
Keyboard light: Fix the physical keyboard not light when it's visiable.

Change-Id: I595afd3cb6b422a17ae0f6ec20aa51979db13810