Contains rx and tx ring context management and certain
firmware commands for netxen firmware v4.0.0+.

This patch gathers all HW context management code into
netxen_nic_ctx.c.
Signed-off-by: NDhananjay Phadke <dhananjay@netxen.com>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>