Add WakeLockQueueFlagBits to Sensors 2.0

WakeLockQueueFlagBits is used to signal between the framework and the
HAL whenever events are available on the Wake Lock FMQ. The
introduction of this type allows for the HAL to utilize blocking calls
when reading the Wake Lock FMQ, if desired.

Also removes stale reference to WakeLockEvent.

Bug: 122528664
Test: Builds, verified Sensors 2.0 default implementation reads events
      when they become available on the Wake Lock FMQ

Change-Id: Ia83bd1642b8f6aa8ea86da05e83f4040c6e593bb