dt-bindings: mmc: convert sdhci-dove to JSON schema

Convert the sdhci-dove binding to JSON schema. The optional clocks
property was not in the original binding document but has been in the
dove.dtsi since commit 5b03df9a ("ARM: dove: switch to DT clock
providers").
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20220419024611.1327525-5-chris.packham@alliedtelesis.co.nzSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Documentation/devicetree/bindings/mmc/marvell,dove-sdhci.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mmc/marvell,dove-sdhci.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Marvell sdhci-dove controller
+
+maintainers:
+  - Adrian Hunter <adrian.hunter@intel.com>
+  - Ulf Hansson <ulf.hansson@linaro.org>
+
+allOf:
+  - $ref: mmc-controller.yaml#
+
+properties:
+  compatible:
+    const: marvell,dove-sdhci
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    minItems: 1
+    maxItems: 2
+
+  clocks:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - interrupts
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    sdio0: mmc@92000 {
+      compatible = "marvell,dove-sdhci";
+      reg = <0x92000 0x100>;
+      interrupts = <35>;
+      clocks = <&gate_clk 9>;
+    };

Documentation/devicetree/bindings/mmc/sdhci-dove.txt

-* Marvell sdhci-dove controller
-
-This file documents differences between the core properties in mmc.txt
-and the properties used by the sdhci-pxav2 and sdhci-pxav3 drivers.
-
-- compatible: Should be "marvell,dove-sdhci".
-
-Example:
-
-sdio0: sdio@92000 {
-	compatible = "marvell,dove-sdhci";
-	reg = <0x92000 0x100>;
-	interrupts = <35>;
-};