dt-bindings: net: marvell,orion-mdio: Fix examples

As stated in marvell-orion-mdio.txt deleted in commit 0781434af811f
("dt-bindings: net: orion-mdio: Convert to JSON schema") if
'interrupts' property is present, width of 'reg' should be 0x84.
Otherwise, width of 'reg' should be 0x4. Fix 'examples:' and add
constraints checking whether 'interrupts' property is present
and validate it against fixed values in reg.

Signed-off-by: Michał Grzelak <[e-mail]>
Reviewed-by: Krzysztof Kozlowski <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

Documentation/devicetree/bindings/net/marvell,orion-mdio.yaml

···
   8k has a second unit which provides an interface with the xMDIO bus. This
   driver handles these interfaces.
 
-allOf:
-  - $ref: "mdio.yaml#"
-
 properties:
   compatible:
     enum:
···
   - compatible
   - reg
 
+allOf:
+  - $ref: mdio.yaml#
+
+  - if:
+      required:
+        - interrupts
+
+    then:
+      properties:
+        reg:
+          items:
+            - items:
+                - $ref: /schemas/types.yaml#/definitions/cell
+                - const: 0x84
+
+    else:
+      properties:
+        reg:
+          items:
+            - items:
+                - $ref: /schemas/types.yaml#/definitions/cell
+                - enum:
+                    - 0x4
+                    - 0x10
+
 unevaluatedProperties: false
 
 examples:
   - |
     mdio@d0072004 {
       compatible = "marvell,orion-mdio";
-      reg = <0xd0072004 0x4>;
+      reg = <0xd0072004 0x84>;
       #address-cells = <1>;
       #size-cells = <0>;
       interrupts = <30>;