hwmon: Driver for ADT7410

This patch brings basic support for the Analog Devices ADT7410 temperature
sensor. The following functionality has been implemented:

  * get current temperature
  * get/set minimum, maximum and critical temperature
  * get/set hysteresis
  * get alarm events for minimum, maximum and critical temperature

All implemented sysfs attributes have been sucessfully tested at temperatures
of 15°C to 40°C.

Signed-off-by: Hartmut Knaack <knaack.h@gmx.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>