netxen_nic: Log proper error message in case of mismatched adapter type

o log "Unknown" board name and "Unknown" serial number in case
  of mismatched adapter type found. This will avoid weird characters
  logs when an adapter is in bad state or corrupted.

Signed-off-by: Manish Chopra <manish.chopra@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>