hwmon/f71882fg: Make all fan/pwm attr tables 2 dimensional

This is a preparation patch for not registering fan/pwm attributes for
some fans (rather then register them for all or for none).

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>