dt-bindings: arm: fsl: Document ifm VHIP4 EvalBoard v1 and v2

Document ifm i.MX8MN VHIP4 EvalBoard v1 and v2 reference design binding.
This system exists in two generations, v1 and v2, which share a lot of
commonality. The boards come with either single gigabit ethernet or an
KSZ8794 fast-ethernet switch, boot from eMMC, and offer CAN interfaces
via Microchip MCP25xx SPI CAN controllers, UART, and USB host. The GPU
is not available in the SoC populated on these devices.

Acked-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Marek Vasut <marex@nabladev.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

Author: Marek Vasut

Documentation/devicetree/bindings/arm/fsl.yaml

@@ -1071,6 +1071,15 @@ properties:
               - gw,imx8mn-gw7902          # i.MX8MM Gateworks Board
           - const: fsl,imx8mn
 
+      - description: ifm i.MX8MN VHIP4 based boards
+        items:
+          - enum:
+              - ifm,imx8mn-vhip4-evalboard-v1
+              - ifm,imx8mn-vhip4-evalboard-v2
+          - const: ifm,imx8mn-vhip4-evalboard
+          - const: ifm,imx8mn-vhip4
+          - const: fsl,imx8mn
+
       - description: Variscite VAR-SOM-MX8MN based boards
         items:
           - enum: