netxen: fix for kdump

When the crash kernel is loaded after crash, the device is in unknown state.
So reset the device contexts prior to its creation in case of kdump,
depending upon kernel parameter reset_devices.

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