dt-bindings: fsl: convert fsl,layerscape-scfg to YAML

Convert the fsl,layerscape-scfg binding to the new YAML format.

In the device trees, the device node always have a "syscon"
compatible, which wasn't mentioned in the previous binding.

Also added, compared to the original binding, is the
interrupt-controller subnode as used in arch/arm/boot/dts/ls1021a.dtsi
as well as the litte-endian and big-endian properties.

Signed-off-by: Michael Walle <[e-mail]>
Reviewed-by: Krzysztof Kozlowski <[e-mail]>
Signed-off-by: Rob Herring <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

Documentation/devicetree/bindings/arm/freescale/fsl,layerscape-scfg.txt

···
-Freescale SCFG
-
-SCFG is the supplemental configuration unit, that provides SoC specific
-configuration and status registers for the chip. Such as getting PEX port
-status.
-
-Required properties:
-  - compatible: Should contain a chip-specific compatible string,
-	Chip-specific strings are of the form "fsl,<chip>-scfg",
-	The following <chip>s are known to be supported:
-	ls1012a, ls1021a, ls1043a, ls1046a, ls2080a.
-
-  - reg: should contain base address and length of SCFG memory-mapped registers
-
-Example:
-	scfg: scfg@1570000 {
-		compatible = "fsl,ls1021a-scfg";
-		reg = <0x0 0x1570000 0x0 0x10000>;
-	};

Documentation/devicetree/bindings/soc/fsl/fsl,layerscape-scfg.yaml

···
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/soc/fsl/fsl,layerscape-scfg.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Freescale Layerscape Supplemental Configuration Unit
+
+maintainers:
+  - Shawn Guo <[e-mail]>
+  - Li Yang <[e-mail]>
+
+description: |
+  SCFG is the supplemental configuration unit, that provides SoC specific
+  configuration and status registers for the chip. Such as getting PEX port
+  status.
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - fsl,ls1012a-scfg
+          - fsl,ls1021a-scfg
+          - fsl,ls1028a-scfg
+          - fsl,ls1043a-scfg
+          - fsl,ls1046a-scfg
+      - const: syscon
+
+  reg:
+    maxItems: 1
+
+  little-endian: true
+  big-endian: true
+
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 1
+
+  ranges: true
+
+patternProperties:
+  "^interrupt-controller@[a-z0-9]+$":
+    $ref: /schemas/interrupt-controller/fsl,ls-extirq.yaml#
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    syscon@1570000 {
+        compatible = "fsl,ls1021a-scfg", "syscon";
+        reg = <0x1570000 0x10000>;
+    };