dt-bindings: bus: convert qcom,ssbi schema to YAML format

Convert arm/msm/ssbi.txt yo YAML, moving it to the directory with bus
bindings.
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230822001349.899298-4-dmitry.baryshkov@linaro.orgSigned-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/arm/msm/ssbi.txt

-* Qualcomm SSBI
-
-Some Qualcomm MSM devices contain a point-to-point serial bus used to
-communicate with a limited range of devices (mostly power management
-chips).
-
-These require the following properties:
-
-- compatible: "qcom,ssbi"
-
-- qcom,controller-type
-  indicates the SSBI bus variant the controller should use to talk
-  with the slave device.  This should be one of "ssbi", "ssbi2", or
-  "pmic-arbiter".  The type chosen is determined by the attached
-  slave.
-
-The slave device should be the single child node of the ssbi device
-with a compatible field.

Documentation/devicetree/bindings/bus/qcom,ssbi.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/bus/qcom,ssbi.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm Single-wire Serial Bus Interface (SSBI)
+
+description:
+  Some Qualcomm MSM devices contain a point-to-point serial bus used to
+  communicate with a limited range of devices (mostly power management
+  chips).
+
+maintainers:
+  - Andy Gross <agross@kernel.org>
+  - Bjorn Andersson <andersson@kernel.org>
+
+properties:
+  compatible:
+    const: qcom,ssbi
+
+  reg:
+    maxItems: 1
+
+  qcom,controller-type:
+    description:
+      Indicates the SSBI bus variant the controller should use to talk
+      with the slave device. The type chosen is determined by the attached
+      slave.
+    enum:
+      - ssbi
+      - ssbi2
+      - pmic-arbiter
+
+  pmic:
+    $ref: /schemas/mfd/qcom-pm8xxx.yaml#
+
+required:
+  - compatible
+  - reg
+  - qcom,controller-type
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    ssbi@c00000 {
+        compatible = "qcom,ssbi";
+        reg = <0x00c00000 0x1000>;
+        qcom,controller-type = "pmic-arbiter";
+
+        pmic {
+            compatible = "qcom,pm8821";
+            interrupt-parent = <&msmgpio>;
+            interrupts = <76 IRQ_TYPE_LEVEL_LOW>;
+            #interrupt-cells = <2>;
+            interrupt-controller;
+            #address-cells = <1>;
+            #size-cells = <0>;
+        };
+    };
+...