dt-bindings: mailbox: imx-mu: add i.MX93 S4 MU support

Similar to i.MX8ULP S4 MU, i.MX93 MU is dedicated for communication
between Sentinel and Cortex-A cores from hardware design, it could not be
reused for other purpose.

However i.MX93 S4 MU use separate tx/rx interrupt, so update
interrupts and add interrupt-names property.
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

Documentation/devicetree/bindings/mailbox/fsl,mu.yaml

@@ -29,6 +29,7 @@ properties:
       - const: fsl,imx8ulp-mu
       - const: fsl,imx8-mu-scu
       - const: fsl,imx8-mu-seco
+      - const: fsl,imx93-mu-s4
       - const: fsl,imx8ulp-mu-s4
       - items:
           - const: fsl,imx93-mu
@@ -55,7 +56,14 @@ properties:
     maxItems: 1
 
   interrupts:
-    maxItems: 1
+    minItems: 1
+    maxItems: 2
+
+  interrupt-names:
+    minItems: 1
+    items:
+      - const: tx
+      - const: rx
 
   "#mbox-cells":
     description: |
@@ -90,6 +98,27 @@ required:
   - interrupts
   - "#mbox-cells"
 
+allOf:
+  - if:
+      properties:
+        compatible:
+          enum:
+            - fsl,imx93-mu-s4
+    then:
+      properties:
+        interrupt-names:
+          minItems: 2
+        interrupts:
+          minItems: 2
+
+    else:
+      properties:
+        interrupts:
+          maxItems: 1
+      not:
+        required:
+          - interrupt-names
+
 additionalProperties: false
 
 examples: