dt-bindings: arm64: mediatek: add Kontron 3.5"-SBC-i1200

Add the compatible string for the Kontron 3.5"-SBC-i1200 single board
computer.
Signed-off-by: Michael Walle <mwalle@kernel.org>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20240408080816.4134370-1-mwalle@kernel.orgSigned-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

Documentation/devicetree/bindings/arm/mediatek.yaml

@@ -367,6 +367,7 @@ properties:
           - const: mediatek,mt8188
       - items:
           - enum:
+              - kontron,3-5-sbc-i1200
               - mediatek,mt8395-evk
               - radxa,nio-12l
           - const: mediatek,mt8395