cxgb4: Calculate len properly for LSO path

Commit 0034b298 ("cxgb4: Don't assume LSO only uses SGL path in t4_eth_xmit()")
introduced a regression where-in length was calculated wrongly for LSO path,
causing chip hangs.
So, correct the calculation of len.

Fixes: 0034b298 ("cxgb4: Don't assume LSO only uses SGL path in t4_eth_xmit()")
Signed-off-by: NKumar Sanghvi <kumaras@chelsio.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/chelsio/cxgb4/sge.c

@@ -1051,7 +1051,6 @@ out_free:	dev_kfree_skb(skb);
 	end = (u64 *)wr + flits;
 
 	len = immediate ? skb->len : 0;
-	len += sizeof(*cpl);
 	ssi = skb_shinfo(skb);
 	if (ssi->gso_size) {
 		struct cpl_tx_pkt_lso *lso = (void *)wr;
@@ -1079,6 +1078,7 @@ out_free:	dev_kfree_skb(skb);
 		q->tso++;
 		q->tx_cso += ssi->gso_segs;
 	} else {
+		len += sizeof(*cpl);
 		wr->op_immdlen = htonl(FW_WR_OP(FW_ETH_TX_PKT_WR) |
 				       FW_WR_IMMDLEN(len));
 		cpl = (void *)(wr + 1);