power/stats: Update HIDL to include power stats API

Adding new power.stats HAL api for subsystem low power stats collection that will eventually replace legacy power stats api.

BUG: 117887759
BUG: 111185513
Test: build successfully
Change-Id: I0da4de378ba0b5daeeb5c2b15435a0c22eff08b4
(cherry picked from commit f836c07b)
Merged-In: I0da4de378ba0b5daeeb5c2b15435a0c22eff08b4