Link: port to new ethtool ETHTOOL_xLINKSETTINGS

      Link: port to new ethtool ETHTOOL_xLINKSETTINGS
This patch defines a new ETHTOOL_GLINKSETTINGS/SLINKSETTINGS API,
handled by the new get_link_ksettings/set_link_ksettings .

This is a WIP version based on this [kernel
patch](https://patchwork.kernel.org/patch/8411401/).

commit 0527f1c

http://github.com/torvalds/linux/commit/3f1ac7a700d039c61d8d8b99f28d605d489a60cfommit
35afb33