hwmon: (f71882fg) Add support for the F81865F

Add support for the Fintek F81865F. It's essentially compatible with
the F71882FG, but has fewer inputs: 7 voltage, 2 temperature and 2 fan
inputs only.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Guenter Roeck <guenter.roeck@ericsson.com>