tf-gerrit-tforg-l1: fix gerrit trigger structure

The review of this job failed the automated sanity check at:

https://review.trustedfirmware.org/c/ci/tf-a-job-configs/+/6217

Fix the trigger to match the documented structure of gerrit triggers at:

https://docs.openstack.org/infra/jenkins-job-builder/triggers.html?highlight=gerrit#triggers.gerrit

So the job can actually be deployed on the server.

Change-Id: Idf2c933536a18eefcb08b885b90c2f2d512d5719
diff --git a/tf-gerrit-tforg-l1.yaml b/tf-gerrit-tforg-l1.yaml
index 3c57368..4b95dfa 100644
--- a/tf-gerrit-tforg-l1.yaml
+++ b/tf-gerrit-tforg-l1.yaml
@@ -100,13 +100,13 @@
     triggers:
     - gerrit:
         server-name: review.trustedfirmware.org
-        projects:
-        - branches:
-          - branch-compare-type: PLAIN
-            branch-pattern: integration
-          project-compare-type: PLAIN
-          project-pattern: TF-A/trusted-firmware-a
         trigger-on:
           - comment-added-event:
-            approval-category: "Allow-CI"
-            approval-value: 1
+              approval-category: "Allow-CI"
+              approval-value: 1
+        projects:
+        - project-compare-type: PLAIN
+          project-pattern: TF-A/trusted-firmware-a
+          branches:
+            - branch-compare-type: PLAIN
+              branch-pattern: integration