ARM: dts: at91: add Microchip EVB-KSZ9477 board

Add KSZ9477 managed switch evaluation kit with SAMA5D36 MPU:
https://www.microchip.com/en-us/development-tool/evb-ksz9477



Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Link: https://lore.kernel.org/r/20211111081045.711323-1-o.rempel@pengutronix.de