netxen: refresh firmware info after reset

o move dma mask update to netxen_start_firmware() so that
  if firmware changes across suspend (e.g. file -> flash)
  it reflects right dma mask.
o re-read firmware capabilities after firmware reset.

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