power: Add new power hints

power: Add new power hints

 * New hint to support CPU boosting with a duration.

libhardware: Add audio power hint

libhardware: Add power hint to set profile

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

libhardware: Add POWER_HINT_LAUNCH_BOOST for PowerHAL

hardware: Add new getFeature() function to Power HAL

 * The current use case for this is to query the power HAL for
   the number of supported profiles.

hardware: Add definition for launch boost info