gl-renderer: display_create needs surface type

In case the base EGLConfig is needed, gl_renderer_display_create() needs to
know it should use EGL_WINDOW_BIT or EGL_PBUFFER_BIT.

The PBUFFER case is added for when the headless backend will grow GL-renderer
support.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>

libweston/backend-x11/x11.c

@@ -1813,6 +1813,7 @@ init_gl_renderer(struct x11_backend *b)
 
 	ret = gl_renderer->display_create(b->compositor, EGL_PLATFORM_X11_KHR,
 					  (void *) b->dpy,
+					  EGL_WINDOW_BIT,
 					  x11_formats,
 					  ARRAY_LENGTH(x11_formats));