ci: don't run everything just because a farm gets re-enabled

Let the other rules take care of this, as they did before
7cf13ea504.

Fixes: 7cf13ea504 ("ci: skip containers & build jobs when disabling a farm")
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25151>

.gitlab-ci/farm-rules.yml

@@ -238,9 +238,8 @@
     - !reference [.freedreno-farm-rules, rules]
 
 
-# Skip container & build jobs when disabling any farm, and run them if any farm
-# gets re-enabled.
-.re-enable-farm-rules:
+# Skip container & build jobs when disabling any farm
+.disable-farm-rules:
   rules:
     # changes(disabled) + exists(disabled) = disabling the farm
     - changes: [ .ci-farms-disabled/microsoft ]
@@ -270,6 +269,3 @@
     - changes: [ .ci-farms-disabled/freedreno ]
       exists: [ .ci-farms-disabled/freedreno ]
       when: never
-    # Any other change to ci-farms-disabled/* means some farm is getting re-enabled
-    - changes: [ .ci-farms-disabled/* ]
-      when: on_success