net: skbuff: Coding: Use eth_type_vlan() instead of open coding it

Fix 'skb_vlan_pop' to use eth_type_vlan instead of directly comparing
skb->protocol to ETH_P_8021Q or ETH_P_8021AD.
Signed-off-by: Shmulik Ladkani <shmulik.ladkani@gmail.com>
Reviewed-by: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/skbuff.c

@@ -4567,8 +4567,7 @@ int skb_vlan_pop(struct sk_buff *skb)
 	if (likely(skb_vlan_tag_present(skb))) {
 		skb->vlan_tci = 0;
 	} else {
-		if (unlikely(skb->protocol != htons(ETH_P_8021Q) &&
-			     skb->protocol != htons(ETH_P_8021AD)))
+		if (unlikely(!eth_type_vlan(skb->protocol)))
 			return 0;
 
 		err = __skb_vlan_pop(skb, &vlan_tci);
@@ -4576,8 +4575,7 @@ int skb_vlan_pop(struct sk_buff *skb)
 			return err;
 	}
 	/* move next vlan tag to hw accel tag */
-	if (likely(skb->protocol != htons(ETH_P_8021Q) &&
-		   skb->protocol != htons(ETH_P_8021AD)))
+	if (likely(!eth_type_vlan(skb->protocol)))
 		return 0;
 
 	vlan_proto = skb->protocol;