dt-bindings: net: dsa: microchip: add internal MDIO bus description

Add description for the internal MDIO bus, including integrated PHY
nodes, to ksz DSA bindings.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20241106075942.1636998-2-o.rempel@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Documentation/devicetree/bindings/net/dsa/microchip,ksz.yaml

@@ -81,6 +81,17 @@ properties:
   interrupts:
     maxItems: 1
 
+  mdio:
+    $ref: /schemas/net/mdio.yaml#
+    unevaluatedProperties: false
+    patternProperties:
+      "^ethernet-phy@[0-9a-f]$":
+        type: object
+        $ref: /schemas/net/ethernet-phy.yaml#
+        unevaluatedProperties: false
+        description:
+          Integrated PHY node
+
 required:
   - compatible
   - reg