nat: Store the config in the connection instead of the lac

This allows that we can print the Nr. next to the lac
and it allows us to change the lac at runtime without
reconnecting the BSC.
diff --git a/openbsc/tests/bsc-nat/bsc_nat_test.c b/openbsc/tests/bsc-nat/bsc_nat_test.c
index 5939632..40e2475 100644
--- a/openbsc/tests/bsc-nat/bsc_nat_test.c
+++ b/openbsc/tests/bsc-nat/bsc_nat_test.c
@@ -332,13 +332,15 @@
 	struct bsc_nat *nat;
 	struct bsc_connection *con;
 	struct bsc_nat_parsed *parsed;
+	struct bsc_config cfg;
 	struct msgb *msg;
 
 	fprintf(stderr, "Testing paging by lac.\n");
 
 	nat = bsc_nat_alloc();
 	con = bsc_connection_alloc(nat);
-	con->lac = 23;
+	con->cfg = &cfg;
+	cfg.lac = 23;
 	con->authenticated = 1;
 	llist_add(&con->list_entry, &nat->bsc_connections);
 	msg = msgb_alloc(4096, "test");
@@ -360,7 +362,7 @@
 	talloc_free(parsed);
 
 	/* Test by finding it */
-	con->lac = 8213;
+	cfg.lac = 8213;
 	copy_to_msg(msg, paging_by_lac_cmd, sizeof(paging_by_lac_cmd));
 	parsed = bsc_nat_parse(msg);
 	if (bsc_nat_find_bsc(nat, msg) != con) {