dt-bindings: remoteproc: mediatek: Improve the rpmsg subnode definition

Improve the definition of the rpmsg subnode by assigning a distinct
node name and adding the definition source of node properties.

Signed-off-by: Tinghan Shen <tinghan.shen@mediatek.com>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20230901080935.14571-2-tinghan.shen@mediatek.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

Documentation/devicetree/bindings/remoteproc/mtk,scp.yaml

@@ -58,6 +58,18 @@ properties:
   memory-region:
     maxItems: 1
 
+  cros-ec-rpmsg:
+    $ref: /schemas/mfd/google,cros-ec.yaml
+    description:
+      This subnode represents the rpmsg device. The properties
+      of this node are defined by the individual bindings for
+      the rpmsg devices.
+
+    required:
+      - mediatek,rpmsg-name
+
+    unevaluatedProperties: false
+
 required:
   - compatible
   - reg
@@ -89,21 +101,7 @@ allOf:
         reg-names:
           maxItems: 2
 
-additionalProperties:
-  type: object
-  description:
-    Subnodes of the SCP represent rpmsg devices. The names of the devices
-    are not important. The properties of these nodes are defined by the
-    individual bindings for the rpmsg devices.
-  properties:
-    mediatek,rpmsg-name:
-      $ref: /schemas/types.yaml#/definitions/string-array
-      description:
-        Contains the name for the rpmsg device. Used to match
-        the subnode to rpmsg device announced by SCP.
-
-  required:
-    - mediatek,rpmsg-name
+additionalProperties: false
 
 examples:
   - |
@@ -118,7 +116,8 @@ examples:
         clocks = <&infracfg CLK_INFRA_SCPSYS>;
         clock-names = "main";
 
-        cros_ec {
+        cros-ec-rpmsg {
+            compatible = "google,cros-ec-rpmsg";
             mediatek,rpmsg-name = "cros-ec-rpmsg";
         };
     };