Input: xpad - change D-PAD mapping on Razer devices

When using Razer Onza controller the dpad doesn't work in many games
because D-PAD was mapped to buttons (useful for dance pads) and not to
HAT0X/Y axis.

ers who really want to have it mapped to buttons can restore previous
behavior by using 'dpad_to_buttons' module option.

Signed-off-by: Thomaz de Oliveira dos Reis <thor27@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>