netxen_nic: disable minidump by default

disable fw dump by default at start up.

Signed-off-by: Sritej Velaga <sritej.velaga@qlogic.com>
Signed-off-by: Rajesh Borundia <rajesh.borundia@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>