mcs7830: unify return value of .ndo_set_mac_address if address is invalid

Unify return value of .ndo_set_mac_address if the given address
isn't valid. Return -EADDRNOTAVAIL as eth_mac_addr() already does
if is_valid_ether_addr() fails.
Signed-off-by: Danny Kukawka <danny.kukawka@bisect.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/usb/mcs7830.c

@@ -239,7 +239,7 @@ static int mcs7830_set_mac_address(struct net_device *netdev, void *p)
 		return -EBUSY;
 
 	if (!is_valid_ether_addr(addr->sa_data))
-		return -EINVAL;
+		return -EADDRNOTAVAIL;
 
 	ret = mcs7830_hif_set_mac_address(dev, addr->sa_data);