ethtool-copy.h: sync with net-next-3.17.0-rc4

This covers kernel changes up to:

commit: f0db9b073415848709dd59a6394969882f517da9
Author: Govindarajulu Varadarajan <_govind@gmx.com>
Date:   Wed Sep 3 03:17:20 2014 +0530

	ethtool: Add generic options for tunables

Signed-off-by: Govindarajulu Varadarajan <_govind@gmx.com>
ethtool: Add rx_copybreak support

Signed-off-by: Govindarajulu Varadarajan <_govind@gmx.com>
ethtool.8.in: Add man page for rx_copybreak

Signed-off-by: Govindarajulu Varadarajan <_govind@gmx.com>