media: dt-bindings: nuvoton: Add NPCM VCD and ECE engine

Add dt-bindings document for Video Capture/Differentiation Engine
(VCD) and Encoding Compression Engine (ECE) present on Nuvoton NPCM
SoCs.

Signed-off-by: Marvin Lin <milkfafa@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>