dt-bindings: arm: aspeed: add Aspeed Evaluation boards

Document the new compatibles used on Aspeed Evaluation boards.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220529104928.79636-3-krzysztof.kozlowski@linaro.org