Add control interface port for GGSN

Change-Id: Ie7232189fe3265a8631fd3652b2c8c152cdee918
Related: OS#1646
diff --git a/include/osmocom/ctrl/ports.h b/include/osmocom/ctrl/ports.h
index 71c8e2d..c89bbe3 100644
--- a/include/osmocom/ctrl/ports.h
+++ b/include/osmocom/ctrl/ports.h
@@ -6,4 +6,5 @@
 #define OSMO_CTRL_PORT_NITB_BSC	4249
 #define OSMO_CTRL_PORT_BSC_NAT	4250
 #define OSMO_CTRL_PORT_SGSN	4251
+#define OSMO_CTRL_PORT_GGSN	4252
 #define OSMO_CTRL_PORT_CSCN	4255