tests/hnb-test: Disable building unsued code

Change-Id: I17f20cea8aa63ed79168653292b99c90b8c03caf
diff --git a/src/tests/hnb-test.c b/src/tests/hnb-test.c
index e6fa7ba..acd8b13 100644
--- a/src/tests/hnb-test.c
+++ b/src/tests/hnb-test.c
@@ -78,6 +78,7 @@
 
 struct msgb *rua_new_udt(struct msgb *inmsg);
 
+#if 0
 static int hnb_test_ue_de_register_tx(struct hnb_test *hnb_test)
 {
 	struct msgb *msg;
@@ -107,6 +108,7 @@
 
 	return osmo_wqueue_enqueue(&hnb_test->wqueue, msg);
 }
+#endif
 
 static int hnb_test_ue_register_tx(struct hnb_test *hnb_test, const char *imsi_str)
 {