iio: Add Freescale mag3110 magnetometer driver

three-axis digital magnetometer with I2C interface

datasheet is available from
http://cache.freescale.com/files/sensors/doc/data_sheet/MAG3110.pdf

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
diff --git a/drivers/iio/magnetometer/Makefile b/drivers/iio/magnetometer/Makefile
index f91b1b6..0f5d3c9 100644
--- a/drivers/iio/magnetometer/Makefile
+++ b/drivers/iio/magnetometer/Makefile
@@ -4,6 +4,7 @@
 
 # When adding new entries keep the list in alphabetical order
 obj-$(CONFIG_AK8975)	+= ak8975.o
+obj-$(CONFIG_MAG3110)	+= mag3110.o
 obj-$(CONFIG_HID_SENSOR_MAGNETOMETER_3D) += hid-sensor-magn-3d.o
 
 obj-$(CONFIG_IIO_ST_MAGN_3AXIS) += st_magn.o