Get rid of separate rtp_port field

Let's use the port part of the struct mgcp_rtp_end->addr field instead
of keeping it separate. This makes it easier passing around and
using/checking the RTP remote address + port, and avoids confusion
having to check stuff outside of the address, with its port part
potentially unset.

Change-Id: I294eb5d85fae79bf62d36eb9e818426e187d442c
diff --git a/tests/mgcp/mgcp_test.c b/tests/mgcp/mgcp_test.c
index e28a574..d843d10 100644
--- a/tests/mgcp/mgcp_test.c
+++ b/tests/mgcp/mgcp_test.c
@@ -1492,7 +1492,7 @@
 	conn = mgcp_conn_get_rtp(endp, conn_id);
 	OSMO_ASSERT(conn);
 	OSMO_ASSERT(conn->end.codec->payload_type == 3);
-	OSMO_ASSERT(conn->end.rtp_port == htons(16434));
+	OSMO_ASSERT(osmo_sockaddr_port(&conn->end.addr.u.sa) == 16434);
 	memset(&addr, 0, sizeof(addr));
 	inet_aton("8.8.8.8", &addr);
 	OSMO_ASSERT(conn->end.addr.u.sa.sa_family == AF_INET);