dt-bindings: arm: sunxi: Add Linutronix Testbox

Add device tree bindings for the newly added Linutronix Testbox board.
Signed-off-by: Bastian Germann <bage@linutronix.de>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>

Documentation/devicetree/bindings/arm/sunxi.yaml

@@ -394,6 +394,12 @@ properties:
           - const: linksprite,pcduino3-nano
           - const: allwinner,sun7i-a20
 
+      - description: Linutronix Testbox v2
+        items:
+          - const: linutronix,testbox-v2
+          - const: lamobo,lamobo-r1
+          - const: allwinner,sun7i-a20
+
       - description: HAOYU Electronics Marsboard A10
         items:
           - const: haoyu,a10-marsboard