hwmon: (f71882fg) Document all supported devices

The list of supported devices was not always well documented in all
places. Clarify and list all devices in documentation, Kconfig and
the driver itself.

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>