dt-bindings: ARM: Document SAMA5D2-ICP

Document device tree binding for SAMA5D2 Industrial Connectivity
Platform(ICP).
Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
[cristian.birsan@microchip.com update board name to match silkscreen]
Signed-off-by: Cristian Birsan <cristian.birsan@microchip.com>
Link: https://lore.kernel.org/r/20200410164320.7658-2-cristian.birsan@microchip.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Documentation/devicetree/bindings/arm/atmel-at91.yaml

@@ -82,6 +82,13 @@ properties:
           - const: atmel,sama5d2
           - const: atmel,sama5
 
+      - description: Microchip SAMA5D2 Industrial Connectivity Platform
+        items:
+          - const: microchip,sama5d2-icp
+          - const: atmel,sama5d27
+          - const: atmel,sama5d2
+          - const: atmel,sama5
+
       - description: SAM9X60-EK board
         items:
           - const: microchip,sam9x60ek