net: dsa: microchip: ksz9477: add Wake on LAN support

Add WoL support for KSZ9477 family of switches. This code was tested on
KSZ8563 chip.

KSZ9477 family of switches supports multiple PHY events:
- wake on Link Up
- wake on Energy Detect.
Since current UAPI can't differentiate between this PHY events, map all
of them to WAKE_PHY.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>