iio: hid-sensors: Added Compass/Magnetometer 3D

Added usage id processing for Compass 3D. This uses IIO
interfaces for triggered buffer to present data to user
mode.This uses HID sensor framework for registering callback
events from the sensor hub.

Signed-off-by: srinivas pandruvada <srinivas.pandruvada@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile
index a6406f7..761f2b6 100644
--- a/drivers/iio/Makefile
+++ b/drivers/iio/Makefile
@@ -18,3 +18,4 @@
 obj-y += dac/
 obj-y += common/
 obj-y += gyro/
+obj-y += magnetometer/