hwmon: (adt7411) add min, max and alarm attributes

This patch adds support for the min, max and alarm attributes of the
voltage and temperature channels. Additionally, the temp2_fault attribute
is supported which indicates a fault of the external temperature diode.
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>