net: Call skb_get_hash in get_xps_queue and __skb_tx_hash

Call standard function to get a packet hash instead of taking this from
skb->sk->sk_hash or only using skb->protocol.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 66f9a04..8b43a28 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2486,7 +2486,7 @@
  * as a distribution range limit for the returned value.
  */
 static inline u16 skb_tx_hash(const struct net_device *dev,
-			      const struct sk_buff *skb)
+			      struct sk_buff *skb)
 {
 	return __skb_tx_hash(dev, skb, dev->real_num_tx_queues);
 }