Merge branch 'ethtool_docs'

Ben Hutchings says:

====================
ethtool: Improve documentation

This series converts most comments in <linux/ethtool.h> into kernel-doc
format, and expands them to describe the semantics as well as I
understand them.  It also fixes some kernel-doc formatting errors.

I started on this at Solarflare, but they graciously allowed me to take
it away and finish it off.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>