nat: Update the tests to make them going again

We now need to have access to a mgcp_cfg and the change to the
setup number patching needs new data. We now set the number to
international type.
diff --git a/openbsc/tests/bsc-nat/bsc_nat_test.c b/openbsc/tests/bsc-nat/bsc_nat_test.c
index 05b06e4..c5edbfe 100644
--- a/openbsc/tests/bsc-nat/bsc_nat_test.c
+++ b/openbsc/tests/bsc-nat/bsc_nat_test.c
@@ -444,6 +444,9 @@
 	nat->bsc_endpoints = talloc_zero_array(nat,
 					       struct bsc_endpoint,
 					       33);
+	nat->mgcp_cfg = mgcp_config_alloc();
+	nat->mgcp_cfg->number_endpoints = 64;
+
 	bsc = bsc_connection_alloc(nat);
 	bsc->cfg = bsc_config_alloc(nat, "foo");
 	bsc_config_add_lac(bsc->cfg, 2323);