Remove support for Wayland

Yes, this is a fancy new feature, but our Wayland support was
particularly bitrotten, and ideally this would be handled by a platform
layer like SDL. If not, we can always add this back in when GLInterface
has caught up. We might be able to even support wxWidgets and GL
together with subsurfaces!

Source/Core/DolphinWX/GLInterface/X11_Util.cpp

@@ -53,11 +53,7 @@ bool cXInterface::Initialize(void *config, void *window_handle)
 
 void *cXInterface::EGLGetDisplay(void)
 {
-#if HAVE_WAYLAND
-	return eglGetDisplay((wl_display *) GLWin.dpy);
-#else
 	return eglGetDisplay(GLWin.dpy);
-#endif
 }
 
 void *cXInterface::CreateWindow(void)