dt-bindings: rtc: Convert sa1100-rtc to json-schema

Convert the sa1100-rtc binding to DT schema format using json-schema.
While add that, add clocks and resets that are actually used.
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Link: https://lore.kernel.org/r/20200616223353.993567-5-lkundrak@v3.skSigned-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/rtc/sa1100-rtc.txt

-* Marvell Real Time Clock controller
-
-Required properties:
-- compatible: should be "mrvl,sa1100-rtc"
-- reg: physical base address of the controller and length of memory mapped
-  region.
-- interrupts: Should be two. The first interrupt number is the rtc alarm
-  interrupt and the second interrupt number is the rtc hz interrupt.
-- interrupt-names: Assign name of irq resource.
-
-Example:
-	rtc: rtc@d4010000 {
-		compatible = "mrvl,mmp-rtc";
-		reg = <0xd4010000 0x1000>;
-		interrupts = <5>, <6>;
-		interrupt-names = "rtc 1Hz", "rtc alarm";
-	};

Documentation/devicetree/bindings/rtc/sa1100-rtc.yaml

+# SPDX-License-Identifier: GPL-2.0-only
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/rtc/sa1100-rtc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Marvell Real Time Clock controller bindings
+
+allOf:
+  - $ref: rtc.yaml#
+
+maintainers:
+  - Alessandro Zummo <a.zummo@towertech.it>
+  - Alexandre Belloni <alexandre.belloni@bootlin.com>
+  - Rob Herring <robh+dt@kernel.org>
+
+properties:
+  compatible:
+    enum:
+      - mrvl,sa1100-rtc
+      - mrvl,mmp-rtc
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  resets:
+    maxItems: 1
+
+  interrupts:
+    minItems: 2
+
+  interrupt-names:
+    items:
+      - const: 'rtc 1Hz'
+      - const: 'rtc alarm'
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - interrupt-names
+
+additionalProperties: false
+
+examples:
+  - |
+    rtc: rtc@d4010000 {
+        compatible = "mrvl,mmp-rtc";
+        reg = <0xd4010000 0x1000>;
+        interrupts = <5>, <6>;
+        interrupt-names = "rtc 1Hz", "rtc alarm";
+    };
+
+...