xserver_xorg-server: Fix typo in wayland configure option

xserver_xorg-server: Fix typo in wayland configure option

Bug was introduced in
https://git.busybox.net/buildroot/commit/package/x11r7/xserver_xorg-server/xserver_xorg-server.mk?id=1370fcaeb7c88e958a967594596769c71a4526f9

The configure option is called --en-/disable-xwayland:
https://cgit.freedesktop.org/xorg/xserver/tree/configure.ac?id=9454cd51da9b38b974cff7c8b7125901f6403848#n630

Fixes
http://autobuild.buildroot.net/results/c32/c32a17509b070b1af497bfc54b85a944fa59ca30/

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>