Bug fix for SensorFusion data rate.

SensorFusion is always returning data at the slowest possible sampling rate (5 Hz). batch() is getting called twice, first time with the requested rate and second time with the slowest rate (which overwrites the requested rate). Fix batch call in SensorFusion::activate()

Bug: 12064319
Change-Id: If62f3e514233f69810336fd22b136b4395b667d3
(cherry picked from commit 88509090)