Networking: Fix a runaway recursion problem introduced the previous fixe for shutting down dup'ed sockets.

net/socket/net_clone.c

@@ -62,6 +62,15 @@
  * Description:
  *   Performs the low level, common portion of net_dupsd() and net_dupsd2()
  *
+ * Input Parameters:
+ *   psock1 - The existing socket that is being cloned.
+ *   psock2 - A reference to an uninitialized socket structure alloated by
+ *            the caller.
+ *
+ * Returned Value:
+ *   Zero (OK) is returned on success; a negated errno value is returned on
+ *   any failure.
+ *
  ****************************************************************************/
 
 int net_clone(FAR struct socket *psock1, FAR struct socket *psock2)