drm/vmwgfx: Remove no-op prepare/cleanup_fb callbacks

Less hits to go through when I git grep over all drivers. These
callbacks are optional.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: VMware Graphics <linux-graphics-maintainer@vmware.com>
Cc: Sinclair Yeh <syeh@vmware.com>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180405154449.23038-2-daniel.vetter@ffwll.ch

drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c

@@ -281,39 +281,6 @@ drm_connector_helper_funcs vmw_ldu_connector_helper_funcs = {
  * Legacy Display Plane Functions
  */
 
-/**
- * vmw_ldu_primary_plane_cleanup_fb - Noop
- *
- * @plane:  display plane
- * @old_state: Contains the FB to clean up
- *
- * Unpins the display surface
- *
- * Returns 0 on success
- */
-static void
-vmw_ldu_primary_plane_cleanup_fb(struct drm_plane *plane,
-				 struct drm_plane_state *old_state)
-{
-}
-
-
-/**
- * vmw_ldu_primary_plane_prepare_fb - Noop
- *
- * @plane:  display plane
- * @new_state: info on the new plane state, including the FB
- *
- * Returns 0 on success
- */
-static int
-vmw_ldu_primary_plane_prepare_fb(struct drm_plane *plane,
-				 struct drm_plane_state *new_state)
-{
-	return 0;
-}
-
-
 static void
 vmw_ldu_primary_plane_atomic_update(struct drm_plane *plane,
 				    struct drm_plane_state *old_state)
@@ -373,8 +340,6 @@ static const struct
 drm_plane_helper_funcs vmw_ldu_primary_plane_helper_funcs = {
 	.atomic_check = vmw_du_primary_plane_atomic_check,
 	.atomic_update = vmw_ldu_primary_plane_atomic_update,
-	.prepare_fb = vmw_ldu_primary_plane_prepare_fb,
-	.cleanup_fb = vmw_ldu_primary_plane_cleanup_fb,
 };
 
 static const struct drm_crtc_helper_funcs vmw_ldu_crtc_helper_funcs = {