NetXen: Port swap feature for multi port cards

NetXen: Port Swap feature
This patch will allow a port numbers on the card to be swapped in
host driver. This feature is applicable to cards having more than
1 port.

Signed-off by: Milan Bag <mbag@netxen.com>
Signed-off by: Mithlesh Thukral <mithlesh@netxen.com>

Signed-off-by: Jeff Garzik <jeff@garzik.org>