sfc: Add support for SFC9000 family (1)

This adds support for the SFC9000 family of 10G Ethernet controllers
and LAN-on-motherboard chips, starting with the SFL9021 'Siena' and
SFC9020 'Bethpage'.

The SFC9000 family is based on the SFC4000 'Falcon' architecture, but
with some significant changes:

- Two ports are associated with two independent PCI functions
  (except SFC9010)
- Integrated 10GBASE-T PHY(s) (SFL9021/9022)
- MAC, PHY and board peripherals are managed by firmware
  - Driver does not require board-specific code
  - Firmware supports wake-on-LAN and lights-out management through NC-SI
- IPv6 checksum offload and RSS
- Filtering by MAC address and VLAN (not included in this code)
- PCI SR-IOV (not included in this code)

Credit for this code is largely due to my colleagues at Solarflare:

   Guido Barzini
   Steve Hodgson
   Kieran Mansley
   Matthew Slattery
   Neil Turton

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>