sctp: implement enqueue_event for sctp_stream_interleave

enqueue_event is added as a member of sctp_stream_interleave, used to
enqueue either data, idata or notification events into user socket rx
queue.

It replaces sctp_ulpq_tail_event used in the other places with
enqueue_event.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sctp/chunk.c b/net/sctp/chunk.c
index 62adaaa..991a530 100644
--- a/net/sctp/chunk.c
+++ b/net/sctp/chunk.c
@@ -124,7 +124,7 @@ static void sctp_datamsg_destroy(struct sctp_datamsg *msg)
 			ev = sctp_ulpevent_make_send_failed(asoc, chunk, sent,
 							    error, GFP_ATOMIC);
 			if (ev)
-				sctp_ulpq_tail_event(&asoc->ulpq, ev);
+				asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
 		}
 
 		sctp_chunk_put(chunk);