staging: fsl-dpaa2/eth: Add ethtool support

Add support for several ethtool operations: show hardware statistics,
get/set link settings, get hash configuration.

Signed-off-by: Ioana Radulescu <ruxandra.radulescu@nxp.com>
Signed-off-by: Bogdan Hamciuc <bogdan.hamciuc@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>