dt-bindings: display: imx: convert fsl,dcu.txt to yaml format

Convert fsl,dcu.txt to yaml format.

Additional changes:
- remove label in example.
- change node to display-controller in example.
- use 32bit address in example.
- add interrupts property.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Stefan Agner <stefan@agner.ch>
Link: https://lore.kernel.org/r/20250616182439.1989840-1-Frank.Li@nxp.com


Signed-off-by: Rob Herring (Arm) <robh@kernel.org>