dt-bindings: remoteproc: imx_rproc: Add minItems for power-domain

"fsl,imx8qxp-cm4" and "fsl,imx8qm-cm4" need minimum 2 power domains. Other
platform doesn't require 'power-domain'.

Signed-off-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20240610151721.274424-1-Frank.Li@nxp.com
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

Documentation/devicetree/bindings/remoteproc/fsl,imx-rproc.yaml

@@ -59,6 +59,7 @@ properties:
     maxItems: 32
 
   power-domains:
+    minItems: 2
     maxItems: 8
 
   fsl,auto-boot:
@@ -99,6 +100,20 @@ allOf:
       properties:
         fsl,iomuxc-gpr: false
 
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - fsl,imx8qxp-cm4
+              - fsl,imx8qm-cm4
+    then:
+      required:
+        - power-domains
+    else:
+      properties:
+        power-domains: false
+
 additionalProperties: false
 
 examples: