bnx2x: MTU for FCoE L2 ring

Always configure an FCoE L2 ring with a mini-jumbo MTU size (2500).
To do that we had to move the rx_buf_size parameter from per
function level to a per ring level.

Signed-off-by: Vladislav Zolotarov <vladz@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/bnx2x/bnx2x_ethtool.c b/drivers/net/bnx2x/bnx2x_ethtool.c
index 5b44a8b..816fef6 100644
--- a/drivers/net/bnx2x/bnx2x_ethtool.c
+++ b/drivers/net/bnx2x/bnx2x_ethtool.c
@@ -1618,7 +1618,7 @@
 	/* prepare the loopback packet */
 	pkt_size = (((bp->dev->mtu < ETH_MAX_PACKET_SIZE) ?
 		     bp->dev->mtu : ETH_MAX_PACKET_SIZE) + ETH_HLEN);
-	skb = netdev_alloc_skb(bp->dev, bp->rx_buf_size);
+	skb = netdev_alloc_skb(bp->dev, fp_rx->rx_buf_size);
 	if (!skb) {
 		rc = -ENOMEM;
 		goto test_loopback_exit;