dt-bindings: arm: at91: Add info on SAMA5D3-EDS

Adding the SAMA5D3-EDS board from Microchip into the atmel AT91 board
description yaml file.

Signed-off-by: Jerry Ray <jerry.ray@microchip.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20220909163022.13022-1-jerry.ray@microchip.com