hwmon: (core) Add support for rated attributes

Adding implementation for new attributes (rated_min/rated_max) for
currentX, inX, powerX, tempX and humidityX.

Tested with OpenBMC stack and simple hwmon driver using
rated_min/rated_max for the following types of sensors: hwmon_temp,
hwmon_in, hwmon_curr, hwmon_power, hwmon_humidity.
For each sensor rated attributes were available and returned
expected values.

Signed-off-by: Zbigniew Lukwinski <zbigniew.lukwinski@linux.intel.com>
Link: https://lore.kernel.org/r/1596224237-32280-3-git-send-email-zbigniew.lukwinski@linux.intel.com


Signed-off-by: Guenter Roeck <linux@roeck-us.net>