gen_fvp_*_yaml.sh: Add Gerrit metadata for LAVA job

To be able to cross-ref LAVA job run to Gerrit change which started it,
if any.

Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
Change-Id: I64085510af8f81d6bf4cb965fd517089c961389c
diff --git a/script/gen_gerrit_meta.sh b/script/gen_gerrit_meta.sh
new file mode 100644
index 0000000..ab58ccb
--- /dev/null
+++ b/script/gen_gerrit_meta.sh
@@ -0,0 +1,17 @@
+#
+# Copyright (c) 2021 Arm Limited. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+
+# Generate Gerrit-related metadata for LAVA job definitions. This is
+# include file is supposed to be sourced from gen_*_yaml.sh files.
+
+if [ -n "${GERRIT_REFSPEC}" ]; then
+    gerrit_url=$(echo ${GERRIT_REFSPEC} |  awk -F/ '{print "https://review.trustedfirmware.org/c/" $4 "/" $5}')
+
+    gerrit_meta="\
+  gerrit_project: ${GERRIT_PROJECT}
+  gerrit_branch: ${GERRIT_BRANCH}
+  gerrit_url: ${gerrit_url}"
+fi