Revert "r8169: improve handling VLAN tag"

This reverts commit 759d095.

The patch was based on a misunderstanding. As Al Viro pointed out [0]
it's simply wrong on big endian. So let's revert it.

[0] https://marc.info/?t=156200975600004&r=1&w=2

Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/realtek/r8169_main.c

@@ -1528,16 +1528,15 @@ static int rtl8169_set_features(struct net_device *dev,
 static inline u32 rtl8169_tx_vlan_tag(struct sk_buff *skb)
 {
 	return (skb_vlan_tag_present(skb)) ?
-		TxVlanTag | htons(skb_vlan_tag_get(skb)) : 0x00;
+		TxVlanTag | swab16(skb_vlan_tag_get(skb)) : 0x00;
 }
 
 static void rtl8169_rx_vlan_tag(struct RxDesc *desc, struct sk_buff *skb)
 {
 	u32 opts2 = le32_to_cpu(desc->opts2);
 
 	if (opts2 & RxVlanTag)
-		__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q),
-				       ntohs(opts2 & 0xffff));
+		__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), swab16(opts2 & 0xffff));
 }
 
 static void rtl8169_get_regs(struct net_device *dev, struct ethtool_regs *regs,