struct ethtool_cmd deprecated

[mpictor]

If you aren't aware, this struct is deprecated as of https://github.com/torvalds/linux/commit/3f1ac7a700d039c61d8d8b99f28d605d489a60cf (2016); the replacement is ethtool_link_settings.

I don't need anything provided by the new interface and not the old - just happened to notice while trying to figure out how to detect that a link was up, and thought I'd give you a heads up. I'm not sure how quickly deprecated interfaces are removed from the kernel, but you probably have several more years.