hwmon: (fschmd) Read voltage scaling factors from BIOS DMI

This patch adds support to the fschmd driver for reading the voltage scaling
factors from BIOS DMI tables, as specified in the Siemens datasheet.

Signed-off-by: Hans de Goede <j.w.r.degoede@hhs.nl>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>