RESEND [PATCH 3/3] NetXen: Graceful teardown of interface and hardware upon module unload

Resending patch 3/3 only.

These changes allow driver close routine to be called during module unload,
to clean-up buffers and other software resources, flush queues etc. Also,
hardware is reset to pristine state.

Signed-off-by: Dhananjay Phadke <dhananjay@netxen.com>
Signed-off-by: Milan Bag <mbag@netxen.com>
Signed-off-by: Wen Xiong <wenxiong@us.ibm.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>