For adding/removing a MAC address, use just one helper each that
handles both unicast and multicast.
Saves one level of indirection for multicast addresses, while improving
the error reporting for unicast addresses.
Signed-off-by: NJulian Wiedmann <jwi@linux.vnet.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>