octeontx2-pf: support to change link speed/duplex/autoneg

commit cea1b117c1b8e8857f6582d3a84c288658aaa0c6 from
git@git.assembla.com:cavium/WindRiver.linux.git

Enable user to change configurations like speed, duplex and
autoneg of network interface via ethtool -s option.

	ethtool -s eth0 advertise 0x1
         --> default values will be passed speed/duplex/an
	ethtool -s eth0 advertise 0x40000 speed 10/1000
                        duplex half/full autoneg on phyad 0x1
	Use phyad 0x1 to overwrite default values

Change-Id: Icdaf8f2bf60801cd81dd293d2ef78a081627b43d
Signed-off-by: Hariprasad Kelam <hkelam@marvell.com>
Reviewed-on: https://sj1git1.cavium.com/c/IP/SW/kernel/linux/+/38066


Tested-by: sa_ip-sw-jenkins <sa_ip-sw-jenkins@marvell.com>
Reviewed-by: Sunil Kovvuri Goutham <Sunil.Goutham@cavium.com>
Signed-off-by: Ruiqiang Hao <Ruiqiang.Hao@windriver.com>