xwayland: Use new DRI2 AuthMagic3

Update for http://cgit.freedesktop.org/xorg/xserver/commit/?h=xwayland-1.12&id=e4566c049c7b385e2307fef3c72ef61762729f42
based on http://cgit.freedesktop.org/xorg/driver/xf86-video-intel/commit/?h=xwayland&id=bb4e7c69349ae1ea6aca36977e0d01bea2966564