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/sequencer/intern/strip_relations.c b/source/blender/sequencer/intern/strip_relations.c
index 1132c4dd69d..f89974b8fef 100644
--- a/source/blender/sequencer/intern/strip_relations.c
+++ b/source/blender/sequencer/intern/strip_relations.c
@@ -250,7 +250,7 @@ void SEQ_relations_free_imbuf(Scene *scene, ListBase *seqbase, bool for_render)
   SEQ_prefetch_stop(scene);
 
   for (seq = seqbase->first; seq; seq = seq->next) {
-    if (for_render && SEQ_time_strip_intersects_frame(scene, seq, CFRA)) {
+    if (for_render && SEQ_time_strip_intersects_frame(scene, seq, scene->r.cfra)) {
       continue;
     }