xwayland: remove protocol.txt - it clashes with xserver-xorg

* Images with wayland-compositors + xwayland + xserver fail to build
* Fedora - they introduced standalone xwayland - does same [1]

[1] https://src.fedoraproject.org/rpms/xorg-x11-server-Xwayland/blob/rawhide/f/xorg-x11-server-Xwayland.spec



Signed-off-by: Andreas Müller <schnitzeltony@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>