vty/ports.h: reserve port 4258 for OsmoHLR VTY

Change-Id: I08cb52d9399a27e6876e45da36f434708c4fddef
diff --git a/include/osmocom/vty/ports.h b/include/osmocom/vty/ports.h
index c5e396b..e43b53f 100644
--- a/include/osmocom/vty/ports.h
+++ b/include/osmocom/vty/ports.h
@@ -24,3 +24,4 @@
 /* 4255 used by control interface */
 #define OSMO_VTY_PORT_MNCC_SIP	4256
 /* 4257 used by control interface */
+#define OSMO_VTY_PORT_HLR	4258