non-iu-build: guard vty libosmo-sigtran function calls.

The function calls osmo_ss7_vty_go_parent() and gtphub_vty_is_config_node()
are not guarded by an ifdef. The functions are only needed for IU
support where libosmo-sigtran is used.

Guard the function calls with a BUILD_IU

Change-Id: I1c609ef0c344ce825c313335c7e084bf97159262
diff --git a/src/gprs/gtphub_main.c b/src/gprs/gtphub_main.c
index 782afb3..c3e25d5 100644
--- a/src/gprs/gtphub_main.c
+++ b/src/gprs/gtphub_main.c
@@ -115,6 +115,7 @@
 	}
 }
 
+#if BUILD_IU
 int gtphub_vty_go_parent(struct vty *vty)
 {
 	switch (vty->node) {
@@ -124,13 +125,16 @@
 
 	return vty->node;
 }
+#endif
 
 int gtphub_vty_is_config_node(struct vty *vty, int node)
 {
 	/* Check if libosmo-sccp declares the node in
 	 * question as config node */
+#if BUILD_IU
 	if (osmo_ss7_is_config_node(vty, node))
 		return 1;
+#endif
 
 	switch (node) {
 	/* add items that are not config */
@@ -145,7 +149,9 @@
 static struct vty_app_info vty_info = {
 	.name 		= "OsmoGTPhub",
 	.version	= PACKAGE_VERSION,
+#if BUILD_IU
 	.go_parent_cb	= gtphub_vty_go_parent,
+#endif
 	.is_config_node	= gtphub_vty_is_config_node,
 };