dt-bindings: soc: fsl: qe: Add an interrupt controller for QUICC Engine Ports

The QUICC Engine provides interrupts for a few I/O ports. This is
handled via a separate interrupt ID and managed via a triplet of
dedicated registers hosted by the SoC.

Implement an interrupt driver for it so that those IRQs can then
be linked to the related GPIOs.

Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/7708243d6cca21004de8b3da87369c06dbee3848.1767804922.git.chleroy@kernel.org
Signed-off-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
[moved from bindings/soc/fsl/cpm_qe/ to bindings/interrupt-controller/ while applying]

Documentation/devicetree/bindings/interrupt-controller/fsl,qe-ports-ic.yaml

@@ -0,0 +1,51 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/interrupt-controller/fsl,qe-ports-ic.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Freescale QUICC Engine I/O Ports Interrupt Controller
+
+maintainers:
+  - Christophe Leroy (CS GROUP) <chleroy@kernel.org>
+
+properties:
+  compatible:
+    enum:
+      - fsl,mpc8323-qe-ports-ic
+
+  reg:
+    maxItems: 1
+
+  interrupt-controller: true
+
+  '#address-cells':
+    const: 0
+
+  '#interrupt-cells':
+    const: 1
+
+  interrupts:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - interrupt-controller
+  - '#address-cells'
+  - '#interrupt-cells'
+  - interrupts
+
+additionalProperties: false
+
+examples:
+  - |
+    interrupt-controller@c00 {
+      compatible = "fsl,mpc8323-qe-ports-ic";
+      reg = <0xc00 0x18>;
+      interrupt-controller;
+      #address-cells = <0>;
+      #interrupt-cells = <1>;
+      interrupts = <74 0x8>;
+      interrupt-parent = <&ipic>;
+    };