Read Sensor Events from Event FMQ

Read sensor events from the Event FMQ whenever the READ_AND_PROCESS
bitmask is set from the Sensors HAL on the Event FMQ.

Bug: 111070257
Test: Compile, configured system to use sensors@2.0 and ensured that
      a_sns_test received events

Change-Id: Iad6b9ef2dc691b8d4f8ba4ae294c1371273be0ba