Input: xpad - add support for Xbox One controllers

Xbox One controllers require an initialization message to start sending
data, so xpad_init_output becomes a required function. The Xbox One
controller does not have LEDs like the Xbox 360 controller, so that
functionality is not implemented. The format of messages controlling rumble
is currently undocumented, so rumble support is not yet implemented.

Note that Xbox One controller advertises three interfaces with the same
interface class, subclass and protocol, so we have to also match against
interface number.

Signed-off-by: Ted Mielczarek <ted@mielczarek.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>