dt-bindings: PCI: ti,j721e-pci-host: add interrupt controller definition

Add missing 'interrupt-controller' property and related subnodes to resolve
the following warning:

arch/arm64/boot/dts/ti/k3-j721s2-common-proc-board.dtb: pcie@2910000: Unevaluated properties are not allowed ('interrupt-controller' was unexpected)
        From schema: Documentation/devicetree/bindings/pci/ti,j721e-pci-host.yaml

Link: https://lore.kernel.org/r/20221025081909.404107-2-mranostay@ti.com
Signed-off-by: Matt Ranostay <mranostay@ti.com>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Acked-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/pci/ti,j721e-pci-host.yaml

@@ -76,6 +76,19 @@ properties:
 
   msi-map: true
 
+  interrupt-controller:
+    type: object
+    additionalProperties: false
+
+    properties:
+      interrupt-controller: true
+
+      '#interrupt-cells':
+        const: 1
+
+      interrupts:
+        maxItems: 1
+
 required:
   - compatible
   - reg