MSC,SGSN: use OSMO_GSUP_PORT == 4222 instead of 2222

In SGSN, actually place the port in the SGSN config by default, so that the
gsup port may now be omitted in the VTY config (the IP address suffices).

Adjust the osmo-sgsn.cfg example.

Depends: I4222e21686c823985be8ff1f16b1182be8ad6175 (libosmocore)
Change-Id: I50f2040e2eb0baacb43849e93cfed10cbc2fc156
diff --git a/doc/examples/osmo-sgsn/osmo-sgsn.cfg b/doc/examples/osmo-sgsn/osmo-sgsn.cfg
index 9703c23..06f035f 100644
--- a/doc/examples/osmo-sgsn/osmo-sgsn.cfg
+++ b/doc/examples/osmo-sgsn/osmo-sgsn.cfg
@@ -11,7 +11,7 @@
  ggsn 0 gtp-version 1
  auth-policy remote
  gsup remote-ip 127.0.0.1
- gsup remote-port 2222
+ gsup remote-port 4222
 !
 ns
  timer tns-block 3