net: bcmgenet: avoid unbalanced enable_irq_wake calls

Multiple enable_irq_wake() calls will keep increasing the IRQ
wake_depth, which ultimately leads to the following types of
situation:

1) enable Wake-on-LAN interrupt w/o password
2) enable Wake-on-LAN interrupt w/ password
3) enable Wake-on-LAN interrupt w/o password
4) disable Wake-on-LAN interrupt

After step 4), GENET would always wake-up the system no matter what
wake-up device we use, which is not what we want. Fix this by making
sure there are no unbalanced enable_irq_wake() calls.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/genet/bcmgenet_wol.c

@@ -86,6 +86,8 @@ int bcmgenet_set_wol(struct net_device *dev, struct ethtool_wolinfo *wol)
 	/* Flag the device and relevant IRQ as wakeup capable */
 	if (wol->wolopts) {
 		device_set_wakeup_enable(kdev, 1);
+		/* Avoid unbalanced enable_irq_wake calls */
+		if (priv->wol_irq_disabled)
 			enable_irq_wake(priv->wol_irq);
 		priv->wol_irq_disabled = false;
 	} else {