max17042_battery: Make it possible to instantiate driver from DT

Allow both device tree (preferred) and platform data-based driver
instantiation.

Signed-off-by: Karol Lewandowski <k.lewandowsk@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>