forcedeth: fix tx limit2 flag check

This is a fix for bug 572201 @ bugs.debian.org

This patch fixes the TX_LIMIT feature flag. The previous logic check
for TX_LIMIT2 also took into account a device that only had TX_LIMIT
set.
Reported-by: Stephen Mulcahu <stephen.mulcahy@deri.org>
Reported-by: Ben Huchings <ben@decadent.org.uk>
Signed-off-by: Ayaz Abdulla <aabdulla@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/forcedeth.c

@@ -5899,7 +5899,7 @@ static int __devinit nv_probe(struct pci_dev *pci_dev, const struct pci_device_i
 	/* Limit the number of tx's outstanding for hw bug */
 	if (id->driver_data & DEV_NEED_TX_LIMIT) {
 		np->tx_limit = 1;
-		if ((id->driver_data & DEV_NEED_TX_LIMIT2) &&
+		if (((id->driver_data & DEV_NEED_TX_LIMIT2) == DEV_NEED_TX_LIMIT2) &&
 		    pci_dev->revision >= 0xA2)
 			np->tx_limit = 0;
 	}