EvdevKeyboard: Numeric keys with CapsLock 'on' output special characters

When CapsLock is on the numeric keys output the special character associated to shift-number key combination even if it should output the number. It seems that QEvdevKeyboardHandler::processKeycode() doesn't remove the shift modifier from the non-letter keys when CapsLock is on.

Reproduced on Beagleboard/EGLFS/Evdev configuration.