smsc75xx: Check for Wake-on-LAN modes

The driver does not check for Wake-on-LAN modes specified by an user,
but will conditionally set the device as wake-up enabled or not based on
that, which could be a very confusing user experience.

Fixes: 6c636503260d ("smsc75xx: add wol magic packet support")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/usb/smsc75xx.c

@@ -731,6 +731,9 @@ static int smsc75xx_ethtool_set_wol(struct net_device *net,
 	struct smsc75xx_priv *pdata = (struct smsc75xx_priv *)(dev->data[0]);
 	int ret;
 
+	if (wolinfo->wolopts & ~SUPPORTED_WAKE)
+		return -EINVAL;
+
 	pdata->wolopts = wolinfo->wolopts & SUPPORTED_WAKE;
 
 	ret = device_set_wakeup_enable(&dev->udev->dev, pdata->wolopts);