osmux: Provide correct local port during mgcp resp

Also document some possible future improvements for local addr.

Change-Id: I12c8fcdc8b772b9f92a70774406d4662f44bd9a9
diff --git a/src/libosmo-mgcp/mgcp_network.c b/src/libosmo-mgcp/mgcp_network.c
index dbed156..650d4c0 100644
--- a/src/libosmo-mgcp/mgcp_network.c
+++ b/src/libosmo-mgcp/mgcp_network.c
@@ -86,7 +86,7 @@
 		}
 	}
 
-	/* Select from preconfigured IP-Addresses */
+	/* Select from preconfigured IP-Addresses. We don't have bind_addr for Osmux (yet?). */
 	if (endp->cfg->net_ports.bind_addr) {
 		/* Check there is a bind IP for the RTP traffic configured,
 		 * if so, use that IP-Address */