Fix default values for CI URL

Change-Id: I70419dbcc3439e4808a146cf4b41063e8ce237ab
Signed-off-by: Zelalem <zelalem.aweke@arm.com>
diff --git a/arm-env.sh b/arm-env.sh
index ca55ef5..ce40ae3 100644
--- a/arm-env.sh
+++ b/arm-env.sh
@@ -15,7 +15,7 @@
 
 # Source repositories.
 arm_gerrit_url="gerrit.oss.arm.com"
-tf_ci_repo_url="http://$arm_gerrit_url/pdswinf/ci/pdcs-platforms/platform-ci"
+tf_ci_repo_url="${CI_SRC_REPO_URL:-http://$arm_gerrit_url/pdswinf/ci/pdcs-platforms/platform-ci}"
 tf_arm_gerrit_repo="ssh://$arm_gerrit_url:29418/pdcs-platforms/ap/tf-topics.git"
 tftf_arm_gerrit_repo="ssh://$arm_gerrit_url:29418/trusted-firmware/tf-a-tests.git"
 scp_src_repo_url="${scp_src_repo_url:-http://$arm_gerrit_url/scp/firmware}"