hwmon: (lm70) Add support for ACPI

This commit adds support for lm70 commpatible drivers with systems that
use ACPI.

Signed-off-by: Andrej Picej <andpicej@gmail.com>
[groeck: Fix various issues seen if CONFIG_ACPI=n]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>