dpc: call updatePowerState instead of post to handler

- When overriding doze screen state, we are already on the same thread.
- Running synchronous here makes it more predictable so that the caller
  can hold and release wake locks.

Test: manual
Bug: 336599466
Change-Id: I20cf9fb08422e32de318c441df3947f613885b0f
1 file changed