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

Convert the fsl,layerscape-dcfg 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.

One thing added here, compared to the original binding is the clock
controller subnode of the LS1028A SoC and its "simple-mfd" compatible as
used in arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi as well as the
little-endian and big-endian properties.
Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220425140433.33936-1-michael@walle.cc

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

-Freescale DCFG
-
-DCFG is the device configuration unit, that provides general purpose
-configuration and status for the device. Such as setting the secondary
-core start address and release the secondary core from holdoff and startup.
-
-Required properties:
-  - compatible: Should contain a chip-specific compatible string,
-	Chip-specific strings are of the form "fsl,<chip>-dcfg",
-	The following <chip>s are known to be supported:
-	ls1012a, ls1021a, ls1043a, ls1046a, ls2080a, lx2160a
-
-  - reg : should contain base address and length of DCFG memory-mapped registers
-
-Example:
-	dcfg: dcfg@1ee0000 {
-		compatible = "fsl,ls1021a-dcfg";
-		reg = <0x0 0x1ee0000 0x0 0x10000>;
-	};

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

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/soc/fsl/fsl,layerscape-dcfg.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Freescale Layerscape Device Configuration Unit
+
+maintainers:
+  - Shawn Guo <shawnguo@kernel.org>
+  - Li Yang <leoyang.li@nxp.com>
+
+description: |
+  DCFG is the device configuration unit, that provides general purpose
+  configuration and status for the device. Such as setting the secondary
+  core start address and release the secondary core from holdoff and
+  startup.
+
+properties:
+  compatible:
+    oneOf:
+      - items:
+          - enum:
+              - fsl,ls1012a-dcfg
+              - fsl,ls1021a-dcfg
+              - fsl,ls1043a-dcfg
+              - fsl,ls1046a-dcfg
+              - fsl,ls1088a-dcfg
+              - fsl,ls2080a-dcfg
+              - fsl,lx2160a-dcfg
+          - const: syscon
+
+      - items:
+          - enum:
+              - fsl,ls1028a-dcfg
+          - const: syscon
+          - const: simple-mfd
+
+  reg:
+    maxItems: 1
+
+  little-endian: true
+  big-endian: true
+
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 1
+
+  ranges: true
+
+patternProperties:
+  "^clock-controller@[0-9a-z]+$":
+    $ref: /schemas/clock/fsl,flexspi-clock.yaml#
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    syscon@1ee0000 {
+        compatible = "fsl,ls1021a-dcfg", "syscon";
+        reg = <0x1ee0000 0x10000>;
+    };