STPK-1429: Fix trigger type for proximity sensor
STPK-1429: Fix trigger type for proximity sensor

The proximity sensor only sends an event if its state changes.

Note the statement at the end of sensor_activate about at least
one event being sent after a sensor is enabled. This will ensure
that whatever middleware components controls the proximity sensor,
it's not going to mistakenly believe that it's stuck in near state.

Change-Id: I56a8bd1ca171cd879d69c03fafab83dde9c42e1e
Signed-off-by: Patrick Porlan <6b7a5b9114e07d350ffba0c179039885a7e82794@intel.com>

01org/android-iio-sensors-hal,01org/android-iio-sensors-hal