redhat: Add packing_test to mod-internal.list

JIRA: https://issues.redhat.com/browse/RHEL-92666
Upstream Status: RHEL-only

Signed-off-by: Petr Oros <poros@redhat.com>

Author: orosp

redhat/mod-internal.list

@@ -104,3 +104,4 @@ ptp_mock
 usbip-core
 usbip-host
 vhci-hcd
+packing_test