osmux: Unify rtp_conn osmux type into a single type

There's no need to separate between BSS and CN side nowadays, the
different types are used nowehere. This separation dates from
osmo-bsc-nat code days.

Change-Id: I65effeddf033eb1955553e8d659c593b4e67f7bc
diff --git a/src/libosmo-mgcp/mgcp_osmux.c b/src/libosmo-mgcp/mgcp_osmux.c
index 85ba655b..abd4f32 100644
--- a/src/libosmo-mgcp/mgcp_osmux.c
+++ b/src/libosmo-mgcp/mgcp_osmux.c
@@ -611,7 +611,7 @@
 
 	conn->osmux.local_cid = (uint8_t) osmux_cid;
 	conn->osmux.local_cid_allocated = true;
-	conn->type = MGCP_OSMUX_BSC;
+	conn->type = MGCP_RTP_OSMUX;
 	return osmux_cid;
 }