Input: xpad - use LED API when identifying wireless controllers

When lighting up the segment identifying wireless controller, Instead of
sending command directly to the controller, let's do it via LED API (usinf
led_set_brightness) so that LED object state is in sync with controller
state and we'll light up the correct segment on resume as well.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>