bnx2x: Fix bridged GSO for 57710/57711 chips

It was recently found out that GSO on 57710/57711 was broken, due to packets
being sent without a valid IP checksum.

Commit 057cf65e "bnx2x: Fix GSO for 57710/57711 chips" partially fixed this
issue, but failed to set the correct IP checksum when receiving GSO packets
via bridges, as such packets enter bnx2x_tx_split() and the FW flags needed
to calculate IP checksum were erroneously set in the incorrect
buffer descriptor.

This patch re-enables GSO in said scenario for 57710/57711 chips.
Signed-off-by: Yuval Mintz <yuvalmin@broadcom.com>
Signed-off-by: Ariel Elior <ariele@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c

@@ -3817,8 +3817,7 @@ netdev_tx_t bnx2x_start_xmit(struct sk_buff *skb, struct net_device *dev)
 			bnx2x_set_pbd_gso_e2(skb, &pbd_e2_parsing_data,
 					     xmit_type);
 		else
-			bnx2x_set_pbd_gso(skb, pbd_e1x, tx_start_bd,
-					  xmit_type);
+			bnx2x_set_pbd_gso(skb, pbd_e1x, first_bd, xmit_type);
 	}
 
 	/* Set the PBD's parsing_data field if not zero