phylink: ensure the PHY interface mode is appropriately set

phylink: ensure the PHY interface mode is appropriately set

[ Upstream commit 182088aa3c6c7f7c20a2c1dcc9ded4a3fc631f38 ]

When setting the ethtool settings, ensure that the validated PHY
interface mode is propagated to the current link settings, so that
2500BaseX can be selected.

Fixes: 9525ae83959b ("phylink: add phylink infrastructure")
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>