board: arcada_ish: add lis2mdl magnetometer

BRANCH=None
BUG=b:128619310
TEST=Validated that iio:device4 is present
TEST=Validate that cat **/iio:device4/in_magn_*_raw prints correct
values
TEST=Ran some CTS tests and verified magnetometer tests pass.
TEST=Opened an android compass app and raw magnetometer reading
app and verified that data is correct.

Change-Id: I79ff5ba8de12686d61e7701ac83689924c4de6c4
Signed-off-by: Yuval Peress <peress@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1535428
Commit-Ready: Jack Rosenthal <jrosenth@chromium.org>
Reviewed-by: Jack Rosenthal <jrosenth@chromium.org>
Reviewed-by: Mathew King <mathewk@chromium.org>
2 files changed