arm64: dts: marvell: split Methode uDPU DTS

Split the Methode uDPU DTS into a common DTSI as preparation for adding
support for Methode eDPU which is based on the uDPU to avoid duplication.

Signed-off-by: Robert Marko <robert.marko@sartura.hr>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>