tg3: Allow for recieve of full-size 8021AD frames

When receiving a vlan-tagged frame that still contains
a vlan header, the length of the packet will be greater
then MTU+ETH_HLEN since it will account of the extra
vlan header.  TG3 checks this for the case for 802.1Q,
but not for 802.1ad.  As a result, full sized 802.1ad
frames get dropped by the card.

Add a check for 802.1ad protocol when receving full
sized frames.
Suggested-by: NPrashant Sreedharan <prashant@broadcom.com>
CC: Prashant Sreedharan <prashant@broadcom.com>
CC: Michael Chan <mchan@broadcom.com>
Signed-off-by: NVladislav Yasevich <vyasevic@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/tg3.c

@@ -6918,7 +6918,8 @@ static int tg3_rx(struct tg3_napi *tnapi, int budget)
 		skb->protocol = eth_type_trans(skb, tp->dev);
 
 		if (len > (tp->dev->mtu + ETH_HLEN) &&
-		    skb->protocol != htons(ETH_P_8021Q)) {
+		    skb->protocol != htons(ETH_P_8021Q) &&
+		    skb->protocol != htons(ETH_P_8021AD)) {
 			dev_kfree_skb_any(skb);
 			goto drop_it_no_recycle;
 		}