ports.h: Add ctrl port for osmo-gbproxy

Change-Id: I46a1cef3013c9bbf9b5a6d64e83cd84568f2523c
diff --git a/include/osmocom/ctrl/ports.h b/include/osmocom/ctrl/ports.h
index d6b5394..b65bd00 100644
--- a/include/osmocom/ctrl/ports.h
+++ b/include/osmocom/ctrl/ports.h
@@ -21,4 +21,5 @@
 #define OSMO_CTRL_PORT_GGSN	4257
 #define OSMO_CTRL_PORT_HLR	4259
 #define OSMO_CTRL_PORT_HNBGW	4262
+#define OSMO_CTRL_PORT_GBPROXY	4263
 /* When adding/changing port numbers, keep docs and wiki in sync. See above. */