ifq: real ifq_start (drain+transmit), dequeue cookie fix, pf_kifq_input hook in the data path; 14/14 suite unchanged

module/include/compat/net/ifq.h

@@ -27,6 +27,7 @@ struct ifqueue {
 	struct mbuf_list	*ifq_free;	/* free list (unused in the port) */
 	unsigned int		 ifq_len;
 	unsigned int		 ifq_oactive;
+	void			*ifq_dequeue;	/* cookie between deq_begin/commit */
 
 	/* statistics */
 	u_int64_t		 ifq_packets;