dts: bindings: dsa: add common bindings file

Added common bindings file for dsa, and adapted NETC to it.

Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>

dts/bindings/dsa/dsa.yaml

@@ -0,0 +1,27 @@
+# Copyright 2025 NXP
+# SPDX-License-Identifier: Apache-2.0
+
+description: DSA Device
+
+child-binding:
+  description: Properties of slave port
+
+  include:
+    - name: pinctrl-device.yaml
+    - name: ethernet-controller.yaml
+      property-allowlist:
+        - zephyr,random-mac-address
+        - local-mac-address
+        - phy-handle
+        - phy-connection-type
+
+  properties:
+    reg:
+      type: array
+      required: true
+      description: Port number
+    ethernet:
+      type: phandle
+      description:
+        A phandle to a valid Ethernet device node. This host
+        device is what the switch port is connected to.

dts/bindings/dsa/nxp,netc-switch.yaml

@@ -5,21 +5,4 @@ description: NXP NETC ethernet switch
 
 compatible: "nxp,netc-switch"
 
-child-binding:
+include: [dsa.yaml]
-  description: Properties of slave port
-
-  include:
-    - name: pinctrl-device.yaml
-    - name: ethernet-controller.yaml
-      property-allowlist:
-        - reg
-        - local-mac-address
-        - phy-handle
-        - phy-connection-type
-
-  properties:
-    ethernet:
-      type: phandle
-      description:
-        A phandle to a valid Ethernet device node. This host
-        device is what the switch port is connected to.