Staging: sxg: Add Ethtool functionality enhancement and misc cleanups

Misc. cleanups in the driver.
* Remove debugging code and variables.
* Fix compile time warnings.
* Remove debugging comments.
* Start cleanup of sxg_stats structure. This structure will eventually become
  very small

Signed-off-by: LinSysSoft Sahara Team <saharaproj@linsyssoft.com>
Signed-off-by: Christopher Harrer <charrer@alacritech.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>