ethtool: switch back from ethtool_keee to ethtool_eee for ioctl

In order to later extend struct ethtool_keee, we have to decouple it
from the userspace format represented by struct ethtool_eee.
Therefore switch back to struct ethtool_eee, representing the userspace
format, and add conversion between ethtool_eee and ethtool_keee.
Struct ethtool_keee will be changed in follow-up patches, therefore
don't do a *keee = *eee here.
Member cmd isn't copied, because it's not used, and we'll remove
it in the next patch of this series. In addition omit setting cmd
to ETHTOOL_GEEE in the ioctl response, userspace ethtool isn't
interested in it.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>