ASCI: Support conference briding with 1..n connections

For each RTP packet that is received from a connection, the mode is
checked whether receiving is allowed or not. If not it is discarded.

In case of "confecho" mode, the RTP is also sent by the receiving
connection.

Then a loop is used to send RTP to all sending endpoints except the one
that received the packet.

Because we have a loop that allows to have 1..n connections, we have no
maximum number of allowed connections anymore.

Change-Id: Ic99a55ab5a3a6170e940403fadd52697e99f2f3a
Related: OS#4853
diff --git a/src/libosmo-mgcp/mgcp_protocol.c b/src/libosmo-mgcp/mgcp_protocol.c
index 978af42..7795734 100644
--- a/src/libosmo-mgcp/mgcp_protocol.c
+++ b/src/libosmo-mgcp/mgcp_protocol.c
@@ -967,7 +967,7 @@
 	}
 
 	/* Check if we are able to accept the creation of another connection */
-	if (llist_count(&endp->conns) >= endp->type->max_conns) {
+	if (endp->type->max_conns > 0 && llist_count(&endp->conns) >= endp->type->max_conns) {
 		LOGPENDP(endp, DLMGCP, LOGL_ERROR,
 			"CRCX: endpoint full, max. %i connections allowed!\n",
 			endp->type->max_conns);