octeontx2-pf: ethtool physical link configuration

Register set_link_ksetting callback with driver such that
link configurations parameters like advertised mode,speed, duplex
and autoneg can be configured.

below command
ethtool -s eth0 advertise 0x1 speed 10 duplex full autoneg on

Signed-off-by: Christina Jacob <cjacob@marvell.com>
Signed-off-by: Sunil Goutham <sgoutham@marvell.com>
Signed-off-by: Hariprasad Kelam <hkelam@marvell.com>
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>