dt-bindings: arm: fsl: Add Marantec maveo box as a DHCOR i.MX6ULL SoM based board

Add Marantec maveo box. The system is used to get a smart conntection
to a door drive. The core of this system is a soldered i.MX6ULL DHCOR
SoM from DH electronics.

Signed-off-by: Christoph Niedermaier <cniedermaier@dh-electronics.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>