ns2: Dump frame relay state to VTY during "show ns"

When doing a "show ns", let's also dump the state of the frame
relay network, with all its links and DLCs (if any).

Change-Id: I798af3e97dc014b6e0fcde86560a1809852f7510
Related: OS#4877
diff --git a/src/gb/gprs_ns2_vty.c b/src/gb/gprs_ns2_vty.c
index b678db4..1ef22f5 100644
--- a/src/gb/gprs_ns2_vty.c
+++ b/src/gb/gprs_ns2_vty.c
@@ -1922,6 +1922,8 @@
 {
 	dump_ns_entities(vty, vty_nsi, false, false);
 	dump_ns_bind(vty, vty_nsi, false);
+	if (vty_fr_network && llist_count(&vty_fr_network->links))
+		osmo_fr_network_dump_vty(vty, vty_fr_network);
 	return CMD_SUCCESS;
 }