jobs/gerrit-pipeline-endianness: ignore submodules

Let the check only run on the main repository, not on any submodules.
This fixes that it would currently fail in osmo-trx: the osmocom-bb
submodule has a copy of libosmocore where the endianness check is known
to be failing (see https://gerrit.osmocom.org/c/osmocom-bb/+/31403).

Change-Id: I795a64a66b4a2e316a99e6b523cc33a9ed364272

jobs/gerrit-pipeline-endianness.yml

@@ -69,8 +69,7 @@
          choosing-strategy: gerrit
          wipe-workspace: true
          skip-tag: true
-         submodule:
-           recursive: false
+         disable-submodules: true
 
     builders:
       - shell: |