Sensors: MultiHal: Increase xfer buffer size

Sensors: MultiHal: Increase xfer buffer size

Increased the size of the sensor event transfer queue from 20 to
36 sensor events.  This size now matches Sensor Services buffer size
that it passes to poll() for reading events and will allow the
multihal to transfer the maximum events possible per poll cycle.

Change-Id: I55459ea0a70b9da848d3d3d43590050d71c53e28