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-tftf-main.yaml b/tf-a-tftf-main.yaml
index 6671478..b04689c 100644
--- a/tf-a-tftf-main.yaml
+++ b/tf-a-tftf-main.yaml
@@ -43,6 +43,11 @@
           default: "+refs/heads/master:refs/remotes/origin/master"
           description: "Git refspec for the Trusted Firmware-A CI scripts."
       - 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: JOBS_REFSPEC
           default: 'refs/heads/master'
           description: |