Merge changes from topic "power.stats HAL"

* changes:
  power/stats: Add VTS test cases for power.stats HAL
  power/stats: Add VTS testcases
  power/stats: Add default implementation
  power/stats: Update HIDL to include power stats API
  power/stats: Update HIDL to use synchronous FMQ
  power.stats: Add power.stats HIDL interface