dt-bindings: arm64: marvell: add solidrun cn9130 som based boards

Add bindings for SolidRun boards based on CN9130 SoM.

Three boards are added in total:
- Clearfog Base
- Clearfog Pro
- SolidWAN
The Clearfog boards are identical to the older Armada 388 based boards,
upgraded with a new SoM and SoC.
However the feature set and performance characteristics are different,
therefore compatible strings from armada 388 versions are not included.

SolidWAN uses the same SoM adding a southbridge on the carrier.

Since 2019 there are bindings in-tree for two boards based on cn9130 and
9131. These are extremely verbose by listing cn9132, cn9131, cn9130,
ap807-quad, ap807 for the SoC alone.
CN9130 SoC combines an application processor (ap807) and a
communication processor (cp115) in a single package.

The communication processor (short CP) is also available separately as a
southbridge. It only functions in combination with the CN9130 SoC.
Complete systems adding one or two southbridges are by convention called
CN9131 and CN9132 respectively.
Despite different naming all systems are built around the same SoC.
Therefore marvell,cn9131 and marvell,cn9132 can be omitted. The number
of CPs is part of a board's BoM and can be reflected in the board
compatible string instead.

Existing bindings also describe cn9130 as a specialisation of
ap807-quad. Usually board-level compatibles stop at the SoC without
going into silicon versions or individual dies.
There is no programming model at this layer, and in particular not for
parts of an SoC. Therefore the ap compatibles can also be omitted.
Signed-off-by: Josua Mayer <josua@solid-run.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>

Documentation/devicetree/bindings/arm/marvell/armada-7k-8k.yaml

@@ -82,4 +82,14 @@ properties:
           - const: marvell,armada-ap807-quad
           - const: marvell,armada-ap807
 
+      - description:
+          SolidRun CN9130 SoM based single-board computers
+        items:
+          - enum:
+              - solidrun,cn9130-clearfog-base
+              - solidrun,cn9130-clearfog-pro
+              - solidrun,cn9131-solidwan
+          - const: solidrun,cn9130-sr-som
+          - const: marvell,cn9130
+
 additionalProperties: true