Don't cache suspend_control service

Caching a reference to the service can lead to a DeadObject if
if the service was restarted. Additially we attempt to wait for
the service if it is not immediately available.

Bug: 160741383
Test: atest FrameworksCoreTests:KernelWakelockReaderTest

Change-Id: If54d644a66bed8a0da6a2f5b34168cad8f954187