dt-bindings: reset: Add YAML schemas for the Intel Reset controller

Add YAML schemas for the reset controller on Intel
Gateway SoC.
Signed-off-by: Dilip Kota <eswara.kota@linux.intel.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

Documentation/devicetree/bindings/reset/intel,rcu-gw.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/reset/intel,rcu-gw.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: System Reset Controller on Intel Gateway SoCs
+
+maintainers:
+  - Dilip Kota <eswara.kota@linux.intel.com>
+
+properties:
+  compatible:
+    enum:
+      - intel,rcu-lgm
+      - intel,rcu-xrx200
+
+  reg:
+    description: Reset controller registers.
+    maxItems: 1
+
+  intel,global-reset:
+    description: Global reset register offset and bit offset.
+    allOf:
+      - $ref: /schemas/types.yaml#/definitions/uint32-array
+      - maxItems: 2
+
+  "#reset-cells":
+    minimum: 2
+    maximum: 3
+    description: |
+      First cell is reset request register offset.
+      Second cell is bit offset in reset request register.
+      Third cell is bit offset in reset status register.
+      For LGM SoC, reset cell count is 2 as bit offset in
+      reset request and reset status registers is same. Whereas
+      3 for legacy SoCs as bit offset differs.
+
+required:
+  - compatible
+  - reg
+  - intel,global-reset
+  - "#reset-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    rcu0: reset-controller@e0000000 {
+        compatible = "intel,rcu-lgm";
+        reg = <0xe0000000 0x20000>;
+        intel,global-reset = <0x10 30>;
+        #reset-cells = <2>;
+    };
+
+    pwm: pwm@e0d00000 {
+        status = "disabled";
+        compatible = "intel,lgm-pwm";
+        reg = <0xe0d00000 0x30>;
+        clocks = <&cgu0 1>;
+        #pwm-cells = <2>;
+        resets = <&rcu0 0x30 21>;
+    };