qlcnic: define error code for loopback test

o Defined error code such as fw not responding, test already running and
  cable not connected.
o Check Fw capability before performing loopback test.

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