Link the switch PHY nodes to the central MDIO controller PCIe endpoint
node on LS1028A (implemented as PF3) so that PHYs are accessible via
MDIO.

Enable SGMII AN on the Felix PCS by telling PHYLINK that the VSC8514
quad PHY is capable of in-band-status.

The PHYs are used in poll mode due to an issue with the interrupt line
on current revisions of the LS1028A-RDB board.
Signed-off-by: Claudiu Manoil <claudiu.manoil@nxp.com>
Signed-off-by: Alex Marginean <alexandru.marginean@nxp.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>