Enable cpp support for IPowerStats AIDL interface am: 5aae5cb79d

Original change: https://android-review.googlesource.com/c/platform/hardware/interfaces/+/1628872

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: Icf4754e16250bfff8d5f8e5c63c5291a5134d2f6