Gigabit ethernet driver for Alacritechs SLIC devices

Hi,

this is the second version of the slicoss gigabit ethernet driver (which is a
rework of the driver from Alacritech which can currently be found under
drivers/staging/slicoss). The driver is supposed to support Mojave, Oasis and
Kalahari cards, for both copper and fiber.

If this code is accepted the staging version can be removed.

The driver has been tested on a SEN2104ET adapter (4 Port PCIe copper).

v2:
- remove unusual padding in statistic strings (suggested by Andrew Lunn)
- for mdio register and bit names use defines from mii.h instead of own ones
  (suggested by Andrew Lunn)
- remove unused defines
- ensure PCI flush at two more places
- use mmiowb before lock to prevent mmio writes leaking out of lock
- fix some typos in comments
- add copyright and GPL header

Regards,
Lino