ci: sync hafnium submodules to internal gerrit

Added necessary support in the scripts to sync three of hafnium
submodules to internal gerrit.

Signed-off-by: Madhukar Pappireddy <madhukar.pappireddy@arm.com>
Change-Id: I2fce3db1bcef0e4a97491bd3e9f64d9866e384f2
diff --git a/arm-env.sh b/arm-env.sh
index 421f0c8..337a4d3 100644
--- a/arm-env.sh
+++ b/arm-env.sh
@@ -25,6 +25,9 @@
 scp_tools_src_repo_url="${scp_tools_src_repo_url:-https://$arm_gerrit_url/scp/tools-non-public}"
 tf_for_scp_tools_src_repo_url="https://$arm_gerrit_url/scp/test-framework"
 spm_arm_gerrit_repo="ssh://$arm_gerrit_url:29418/trusted-firmware/spm.git"
+spm_proj_ref_arm_gerrit_repo="ssh://$arm_gerrit_url:29418/trusted-firmware/spm/project/reference.git"
+spm_prebuilts_arm_gerrit_repo="ssh://$arm_gerrit_url:29418/trusted-firmware/spm/prebuilts.git"
+spm_driver_linux_arm_gerrit_repo="ssh://$arm_gerrit_url:29418/trusted-firmware/spm/driver/linux.git"
 
 # Arm Coverity server.
 export coverity_host="${coverity_host:-coverity.cambridge.arm.com}"