dt-bindings: net: Convert Calxeda Ethernet binding to json-schema

Convert the Calxeda XGMAC Ethernet device binding to DT schema format
using json-schema.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/net/calxeda-xgmac.txt

-* Calxeda Highbank 10Gb XGMAC Ethernet
-
-Required properties:
-- compatible : Should be "calxeda,hb-xgmac"
-- reg : Address and length of the register set for the device
-- interrupts : Should contain 3 xgmac interrupts. The 1st is main interrupt.
-  The 2nd is pwr mgt interrupt. The 3rd is low power state interrupt.
-
-Optional properties:
-- dma-coherent      : Present if dma operations are coherent
-
-Example:
-
-ethernet@fff50000 {
-        compatible = "calxeda,hb-xgmac";
-        reg = <0xfff50000 0x1000>;
-        interrupts = <0 77 4  0 78 4  0 79 4>;
-};

Documentation/devicetree/bindings/net/calxeda-xgmac.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/net/calxeda-xgmac.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Calxeda Highbank 10Gb XGMAC Ethernet controller
+
+description: |
+  The Calxeda XGMAC Ethernet controllers are directly connected to the
+  internal machine "network fabric", which is set up, initialised and
+  managed by the firmware. So there are no PHY properties in this
+  binding. Switches in the fabric take care of routing and mapping the
+  traffic to external network ports.
+
+maintainers:
+  - Andre Przywara <andre.przywara@arm.com>
+
+properties:
+  compatible:
+    const: calxeda,hb-xgmac
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    description: |
+      Can point to at most 3 xgmac interrupts. The 1st one is the main
+      interrupt, the 2nd one is used for power management. The optional
+      3rd one is the low power state interrupt.
+    minItems: 2
+    maxItems: 3
+
+  dma-coherent: true
+
+required:
+  - compatible
+  - reg
+  - interrupts
+
+additionalProperties: false
+
+examples:
+  - |
+    ethernet@fff50000 {
+        compatible = "calxeda,hb-xgmac";
+        reg = <0xfff50000 0x1000>;
+        interrupts = <0 77 4>, <0 78 4>, <0 79 4>;
+    };