netxen: fix set mac addr

o If tx and rx resources are not available, during set mac request.
  Then this request wont be passed to firmware and it will be added to
  driver mac list and will never make it to firmware.
  So if resources are not available, don't add it to driver mac list.

Signed-off-by: Amit Kumar Salecha <amit.salecha@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>