Cleanup: Remove scene frame macros (`CFRA` et al.)

Removes the following macros for scene/render frame values:
- `CFRA`
- `SUBFRA`
- `SFRA`
- `EFRA`

These macros don't add much, other than saving a few characters when typing.
It's not immediately clear what they refer to, they just hide what they
actually access. Just be explicit and clear about that.
Plus these macros gave read and write access to the variables, so eyesores like
this would be done (eyesore because it looks like assigning to a constant):
```
CFRA = some_frame_nbr;
```

Reviewed By: sergey

Differential Revision: https://developer.blender.org/D15311

1 files changed, 1 insertions, 1 deletions

diff --git a/source/blender/blenkernel/intern/image.cc b/source/blender/blenkernel/intern/image.cc
index afde8893b93..0c4dc3c87f3 100644
--- a/source/blender/blenkernel/intern/image.cc
+++ b/source/blender/blenkernel/intern/image.cc
@@ -1582,7 +1582,7 @@ static void stampdata(
   }
 
   if (use_dynamic && scene->r.stamp & R_STAMP_MARKER) {
-    const char *name = BKE_scene_find_last_marker_name(scene, CFRA);
+    const char *name = BKE_scene_find_last_marker_name(scene, scene->r.cfra);
 
     if (name) {
       STRNCPY(text, name);