ci/etnaviv: if farm is down, we expect no manual jobs can be triggered

Reviewed-by: Martin Roukala (né Peres) <martin.roukala@mupuf.org>
Acked-by: Daniel Stone <daniels@collabora.com>
Signed-off-by: David Heidelberg <david.heidelberg@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/23629>

.gitlab-ci/test-source-dep.yml

@@ -994,6 +994,7 @@
   stage: etnaviv
   retry: *scheduled-pipeline-retries
   rules:
+    - !reference [.austriancoder-farm-rules, rules]
     - !reference [.gl-manual-rules, rules]
     - changes:
         *etnaviv_file_list