endp: do not cache cfg pointer

There is no obvious reason why we would want to complicate the code by
caching pointers, since pointer traversal is probably not a performance
bottleneck, and if it is we should rather take a look at our dozens of
linked lists first..

Change-Id: I2456ba63598f76200d53e00223abf60bb36a49c0
diff --git a/src/libosmo-mgcp/mgcp_conn.c b/src/libosmo-mgcp/mgcp_conn.c
index ca12347..4acf18c 100644
--- a/src/libosmo-mgcp/mgcp_conn.c
+++ b/src/libosmo-mgcp/mgcp_conn.c
@@ -143,7 +143,7 @@
 
 void mgcp_conn_watchdog_kick(struct mgcp_conn *conn)
 {
-	int timeout = conn->endp->cfg->conn_timeout;
+	int timeout = conn->endp->trunk->cfg->conn_timeout;
 	if (!timeout)
 		return;