power: supply: max17042_battery: Convert to i2c's .probe_new()

.probe_new() doesn't get the i2c_device_id * parameter, so determine
that explicitly in the probe function.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>