use 'main' branch of RMM by default in all Job configs

Use 'main' branch of RMM by default during cloning in all job configs.

Change-Id: If92cf2026c9784dd4b677c556d5a8726a38ae3a0
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
diff --git a/tf-a-arm-weekly.yaml b/tf-a-arm-weekly.yaml
index 2da6595..90e5e5e 100644
--- a/tf-a-arm-weekly.yaml
+++ b/tf-a-arm-weekly.yaml
@@ -38,6 +38,11 @@
            description: |
              SPM(Hafnium) refspec to use. The master branch is used by default.
         - string:
+           name: RMM_REFSPEC
+           default: '+refs/heads/main:refs/remotes/origin/main'
+           description: |
+             tf-rmm refspec to use. The main branch is used by default.
+        - string:
             name: CI_REFSPEC
             default: '+refs/heads/master:refs/remotes/origin/master'
         - string: