Staging: add sxg network driver

This is the first rough cut at a driver for the Alacritech SLIC
Technology Non-Accelerated 10Gbe network driver

TODO:
  - lindent the code
  - remove typedefs
  - remove wrappers
  - checkpatch.pl cleanups
  - new functionality that the card needs

Cc: Christopher Harrer <charrer@alacritech.com>
Cc: Michael Miles <mmiles@alacritech.com>
Cc: Christopher Harrer <charrer@alacritech.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>