dt-bindings: net: dsa: qca8k: utilize shared dsa.yaml

The dsa.yaml binding contains duplicated bindings for address and size
cells, as well as the reference to dsa-port.yaml. Instead of duplicating
this information, remove the reference to dsa-port.yaml and include the
full reference to dsa.yaml.
Signed-off-by: NColin Foster <colin.foster@in-advantage.com>
Suggested-by: NVladimir Oltean <olteanv@gmail.com>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Reviewed-by: NRob Herring <robh@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/dsa/qca8k.yaml

@@ -66,15 +66,11 @@ properties:
                  With the legacy mapping the reg corresponding to the internal
                  mdio is the switch reg with an offset of -1.
 
+$ref: "dsa.yaml#"
+
 patternProperties:
   "^(ethernet-)?ports$":
     type: object
-    properties:
-      '#address-cells':
-        const: 1
-      '#size-cells':
-        const: 0
-
     patternProperties:
       "^(ethernet-)?port@[0-6]$":
         type: object
@@ -116,7 +112,7 @@ required:
   - compatible
   - reg
 
-additionalProperties: true
+unevaluatedProperties: false
 
 examples:
   - |