dt-bindings: PCI: brcm,iproc-pcie: Fix 'msi' child node schema

The 'msi' child node schema is missing constraints on additional properties.
It turns out it is incomplete and properties for it are documented in the
parent node by mistake. Move the reference to msi-controller.yaml and
the custom properties to the 'msi' node. Adding 'unevaluatedProperties'
ensures all the properties in the 'msi' node are documented.

With the schema corrected, a minimal interrupt controller node is needed
to properly decode the interrupt properties since the example has
multiple interrupt parents.
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Fixes: 905b986d ("dt-bindings: pci: Convert iProc PCIe to YAML")
Link: https://lore.kernel.org/r/20230926155613.33904-3-robh@kernel.orgSigned-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/pci/brcm,iproc-pcie.yaml

@@ -12,7 +12,6 @@ maintainers:
 
 allOf:
   - $ref: /schemas/pci/pci-bus.yaml#
-  - $ref: /schemas/interrupt-controller/msi-controller.yaml#
 
 properties:
   compatible:
@@ -63,20 +62,24 @@ properties:
 
   msi:
     type: object
+    $ref: /schemas/interrupt-controller/msi-controller.yaml#
+    unevaluatedProperties: false
+
     properties:
       compatible:
         items:
           - const: brcm,iproc-msi
 
-  msi-parent: true
+      interrupts:
+        maxItems: 4
 
-  msi-controller: true
+      brcm,pcie-msi-inten:
+        type: boolean
+        description:
+          Needs to be present for some older iProc platforms that require the
+          interrupt enable registers to be set explicitly to enable MSI
 
-  brcm,pcie-msi-inten:
-    type: boolean
-    description: >
-      Needs to be present for some older iProc platforms that require the
-      interrupt enable registers to be set explicitly to enable MSI
+  msi-parent: true
 
 dependencies:
   brcm,pcie-ob-axi-offset: ["brcm,pcie-ob"]
@@ -104,6 +107,11 @@ examples:
   - |
     #include <dt-bindings/interrupt-controller/arm-gic.h>
 
+    gic: interrupt-controller {
+        interrupt-controller;
+        #interrupt-cells = <3>;
+    };
+
     pcie@18012000 {
         compatible = "brcm,iproc-pcie";
         reg = <0x18012000 0x1000>;