bindings: add support for qcom,ucsi-glink

The UCSI Glink device handles the communication between OPM on
the Application processor and PPM which is charger firmware
running on the remote subsystem (e.g. DSP) over PMIC Glink.

Change-Id: I1ff3756302c40c88954109b6dccaf87e59e66919

bindings/usb/qcom,ucsi-glink.txt

@@ -0,0 +1,26 @@
+QTI UCSI binding
+
+This binding describes the Qualcomm Technologies, Inc. UCSI device. UCSI
+handles the communication between OPM on the Application processor and PPM
+which is charger firmware running on the remote subsystem (e.g. DSP) over
+PMIC Glink.
+
+Refer to Documentation/devicetree/bindings/soc/qcom/qcom,pmic-glink.txt for
+information on "qcom,pmic_glink" device which is used in the example below.
+
+- compatible:
+	Usage: required
+	Value type: <stringlist>
+	Definition: must be "qcom,ucsi-glink"
+
+= EXAMPLE
+
+&soc {
+	qcom,pmic_glink {
+		...
+		qcom,ucsi {
+			compatible = "qcom,ucsi-glink";
+		};
+		...
+	};
+};