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 <[e-mail]>
Reported-by: Ben Huchings <[e-mail]>
Signed-off-by: Ayaz Abdulla <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/forcedeth.c

···
 	/* 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;
 	}