dts: arm: at91: Add SAMA5D3-EDS Board

The SAMA5D3-EDS board is an Ethernet Development Platform allowing for
evaluating many Microchip ethernet switch and PHY products.  Various
daughter cards can connect via an RGMII connector or an RMII connector.

The EDS board is not intended for stand-alone use and has no ethernet
capabilities when no daughter board is connected.  As such, this device
tree is intended to be used with a DT overlay defining the add-on board.
To better ensure consistency, some items are defined here as a form of
documentation so that all add-on overlays will use the same terms.

Link: https://www.microchip.com/en-us/development-tool/SAMA5D3-ETHERNET-DEVELOPMENT-SYSTEM


Signed-off-by: Jerry Ray <jerry.ray@microchip.com>
[claudiu.beznea: s/gpio-inputs/gpio-keys in at91-sama5d3_eds.dts]
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20220909163022.13022-2-jerry.ray@microchip.com