net: lan743x: Add support to ethtool phylink get and set settings

Add support to ethtool phylink functions:
  - get/set settings like speed, duplex etc
  - get/set the wake-on-lan (WOL)
  - get/set the energy-efficient ethernet (EEE)
  - get/set the pause

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Raju Lakkaraju <Raju.Lakkaraju@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>