[mutter/gbsneto/graphene-frustrum: 13/17] clutter/stage: Remove outdated comment

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit f565cb8a5963ac08d3da3ae8585df9f851857567
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Fri Oct 9 20:54:14 2020 -0300

    clutter/stage: Remove outdated comment
    
    https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1489

 clutter/clutter/clutter-stage.c | 5 -----
 1 file changed, 5 deletions(-)
---
diff --git a/clutter/clutter/clutter-stage.c b/clutter/clutter/clutter-stage.c
index 8d934111fa..98ca6a8016 100644
--- a/clutter/clutter/clutter-stage.c
+++ b/clutter/clutter/clutter-stage.c
@@ -730,11 +730,6 @@ _cogl_util_get_eye_planes_for_screen_poly (float                    *polygon,
                                        tmp_poly,
                                        n_vertices * 2);
 
-  /* XXX: It's quite ugly that we end up with these casts between
-   * Vector4 types and CoglVector3s, it might be better if the
-   * cogl_vector APIs just took pointers to floats.
-   */
-
   for (i = 0; i < n_vertices; i++)
     {
       graphene_point3d_t p[3];