dt-bindings: Add qfprom-sys documentation

qfprom-sys can be used to export nvmem cell values as sysfs
entries to user space.

Change-Id: I2bcbf1bbfc0ac187e6f2b7c177b0f2bc14ca654e

bindings/arm/msm/qcom,qfprom-sys.yaml

@@ -0,0 +1,36 @@
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/bindings/arm/msm/qcom,qfprom-sys.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm Technologies, Inc. QFPROM_SYS driver binding
+
+maintainers:
+
+description: |+
+  QFPROM_SYS provides access to the nvmem cells to the user space.
+  The driver exports the cell values as sysfs entries.
+
+properties:
+  compatible:
+    const: qcom,qfprom-sys
+
+  nvmem-cell-name:
+    description: array of strings for cell names
+
+  nvmem-cells:
+    description: phandle to particular cell from provider
+
+required:
+  - compatible
+  - nvmem-cell-name
+  - nvmem-cells
+
+example:
+  - |
+    qfprom@0 {
+        compatible = "qcom,qfprom-sys";
+        nvmem-cells = <&tsens_calibration1>, <&tsens_calibration2>;
+        nvmem-cell-names = "calibration1", "calibration2";
+    };
+...