dt-bindings: dma: Convert mtk-uart-apdma to DT schema

Convert the MediaTek UART APDMA Controller binding to DT schema.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20220217095242.13761-1-angelogioacchino.delregno@collabora.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>