iio: accel: Add driver for dmard10 3-axis Accelerometer

Add a driver for the Domintech ARD10 3-axis Accelerometer, based on the
android driver found here: https://github.com/domintech/dmard10



Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>