fixup mgcp_trunk: increase default number of virtual endpoints

In change I55605ea083565b6950d0820e3f72c50c9dc19ffa, the default
number of endpoints was increased to 512, however the
configuration examples were not updated.

Change-Id: I449a612065a5208c9f70ae74f594e8d45eb344cf
Related: OS#4711, SYS#5262
diff --git a/doc/examples/osmo-mgw/osmo-mgw-abis_e1.cfg b/doc/examples/osmo-mgw/osmo-mgw-abis_e1.cfg
index abdcb04..6d369ef 100644
--- a/doc/examples/osmo-mgw/osmo-mgw-abis_e1.cfg
+++ b/doc/examples/osmo-mgw/osmo-mgw-abis_e1.cfg
@@ -13,7 +13,7 @@
   bind port 2427
   sdp audio payload number 98
   sdp audio payload name GSM
-  number endpoints 31
+  number endpoints 512
   loop 0
   force-realloc 1
   rtcp-omit
diff --git a/doc/examples/osmo-mgw/osmo-mgw.cfg b/doc/examples/osmo-mgw/osmo-mgw.cfg
index dca858e..ea00f6c 100644
--- a/doc/examples/osmo-mgw/osmo-mgw.cfg
+++ b/doc/examples/osmo-mgw/osmo-mgw.cfg
@@ -10,7 +10,7 @@
   bind port 2427
   sdp audio payload number 98
   sdp audio payload name GSM
-  number endpoints 31
+  number endpoints 512
   loop 0
   force-realloc 1
   rtcp-omit