hwmon: Add LTC4245 driver

Add Linux support for the Linear Technology LTC4245 Multiple Supply Hot
Swap controller I2C monitoring interface.

Signed-off-by: Ira W. Snyder <iws@ovro.caltech.edu>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>