st/xorg: Include u_surface.h for u_copy_rect

Fixes build errors.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Brian Paul <brianp@vmware.com>

src/gallium/state_trackers/xorg/xorg_crtc.c

 #include "state_tracker/drm_driver.h"
 #include "util/u_inlines.h"
 #include "util/u_rect.h"
+#include "util/u_surface.h"
 
 #ifdef HAVE_LIBKMS
 #include "libkms/libkms.h"