tun, rfs: fix the incorrect hash value

The code incorrectly save the queue index as the hash, so this patch
is fixing it with the hash received in the stack receive path.
Signed-off-by: NZhi Yong Wu <wuzhy@linux.vnet.ibm.com>
Acked-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/tun.c

@@ -378,8 +378,8 @@ static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb)
 	if (txq) {
 		e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
 		if (e) {
-			txq = e->queue_index;
 			tun_flow_save_rps_rxhash(e, txq);
+			txq = e->queue_index;
 		} else
 			/* use multiply and shift instead of expensive divide */
 			txq = ((u64)txq * numqueues) >> 32;