netxen: fix firmware download

o hold the firmware in memory across suspend, since filesystem
  may not be up after resuming.
o reset the chip after requesting firmware, to minimize downtime
  for NC-SI.

Signed-off-by: Dhananjay Phadke <dhananjay@netxen.com>
Signed-off-by: David S. Miller <davem@davemloft.net>