hnbgw: vty: set explicit go_parent_cb

A second level of depth will be added to the hnbgw node soon, which will need
explicit go-parent logic.

Change-Id: I8d1c18a396c215e8425ae49872b5c73316087d7d
diff --git a/src/hnbgw_vty.c b/src/hnbgw_vty.c
index ff75aea..a458c76 100644
--- a/src/hnbgw_vty.c
+++ b/src/hnbgw_vty.c
@@ -54,6 +54,27 @@
 	return CMD_SUCCESS;
 }
 
+int hnbgw_vty_go_parent(struct vty *vty)
+{
+	switch (vty->node) {
+	case IUH_NODE:
+		vty->node = HNBGW_NODE;
+		vty->index = NULL;
+		break;
+	default:
+	case HNBGW_NODE:
+		vty->node = CONFIG_NODE;
+		vty->index = NULL;
+		break;
+	case CONFIG_NODE:
+		vty->node = ENABLE_NODE;
+		vty->index = NULL;
+		break;
+	}
+
+	return vty->node;
+}
+
 static void vty_dump_hnb_info(struct vty *vty, struct hnb_context *hnb)
 {
 	struct hnbgw_context_map *map;