PowerManagerService: open power HAL less aggressively

Once the power HAL has failed to open once, don't try to open it again
on subsequent calls to the service.

Test: remove power HAL on marlin & confirm log spam stops.
Bug: 38028137
Change-Id: If7bc4f7080e8822b68da0d1bd81df8de1ce388aa
Signed-off-by: Connor O'Brien <connoro@google.com>