gbproxy: Add config option to name an SGSN

This is useful for logging and configuration to identify an SGSN by name

Change-Id: I2a3410dd9bebb242957e13a63ed70e447204203c
Related: SYS#5115, OS#4472
diff --git a/doc/examples/osmo-gbproxy/osmo-gbproxy-pool.cfg b/doc/examples/osmo-gbproxy/osmo-gbproxy-pool.cfg
index a5e8967..bbc8a1b 100644
--- a/doc/examples/osmo-gbproxy/osmo-gbproxy-pool.cfg
+++ b/doc/examples/osmo-gbproxy/osmo-gbproxy-pool.cfg
@@ -9,6 +9,7 @@
   nri bitlen 4
   nri null add 0 4
 sgsn nsei 101
+ name main
  nri add 1
  nri add 11
 sgsn nsei 102