Write to Wake Lock FMQ

Write the number of WAKE_UP sensor events handled by the Sensor
Service to the Wake Lock FMQ. This allows the Sensors HAL to release
its wake lock for events once the Sensor Service holds a wake lock for
the events.

Bug: 111070257
Test: Compile, configured system to use sensors@2.0 and ensured that
      a_sns_test received events
Test: Ensured device with sensors@1.0 receives events as expected
Change-Id: Ide091012bdaeb2e6a9fc4f5a43ddbb298dbf3416