ixgbe: do not clear FCoE DDP error status for received ABTS

The ddp->err is initialized to be 1 to make sure outstanding DDP context is
guaranteed to be invalidated when HW is not auto-invalidating it. However,
in case of receiving ABTS response for a DDPed I/O, the ddp->err was cleared,
bypassing the invalidating of the DDP context from upper protocol stack when
ixgbe_fcoe_ddp_put() is called. This bug is fixed here by updating the error
only when FCP_RSP is received.

Signed-off-by: Yi Zou <[e-mail]>
Tested-by: Ross Brattain <[e-mail]>
Signed-off-by: Jeff Kirsher <[e-mail]>

drivers/net/ixgbe/ixgbe_fcoe.c

···
 	if (!ddp->udl)
 		goto ddp_out;
 
-	ddp->err = (fcerr | fceofe);
-	if (ddp->err)
+	if (fcerr | fceofe)
 		goto ddp_out;
 
 	fcstat = (sterr & IXGBE_RXDADV_STAT_FCSTAT);
···
 		if (fcstat == IXGBE_RXDADV_STAT_FCSTAT_FCPRSP) {
 			pci_unmap_sg(adapter->pdev, ddp->sgl,
 				     ddp->sgc, DMA_FROM_DEVICE);
+			ddp->err = (fcerr | fceofe);
 			ddp->sgl = NULL;
 			ddp->sgc = 0;
 		}