libhardware: Add power hint to set profile

 * A PowerHAL can implement support for this hint to receive
   power profile changes from the framework.

Change-Id: Ie1e9e3b827c731cf5a817a0491677e3451fe8678

Conflicts:
	include/hardware/power.h
Merge branch 'kk-4.4.3' of https://github.com/Mahdi-Rom/android_hardware_libhardware into kk-4.4