nvmem: qfprom: Add bindings for qfprom

This patch adds bindings for qfprom found in QCOM SOCs. QFPROM driver
is based on simple nvmem framework.
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Tested-by: Philipp Zabel <p.zabel@pengutronix.de>
Tested-by: Rajendra Nayak <rnayak@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/nvmem/qfprom.txt

+= Qualcomm QFPROM device tree bindings =
+
+This binding is intended to represent QFPROM which is found in most QCOM SOCs.
+
+Required properties:
+- compatible: should be "qcom,qfprom"
+- reg: Should contain registers location and length
+
+= Data cells =
+Are child nodes of qfprom, bindings of which as described in
+bindings/nvmem/nvmem.txt
+
+Example:
+
+	qfprom: qfprom@00700000 {
+		compatible 	= "qcom,qfprom";
+		reg		= <0x00700000 0x8000>;
+		...
+		/* Data cells */
+		tsens_calibration: calib@404 {
+			reg = <0x4404 0x10>;
+		};
+	};
+
+
+= Data consumers =
+Are device nodes which consume nvmem data cells.
+
+For example:
+
+	tsens {
+		...
+		nvmem-cells = <&tsens_calibration>;
+		nvmem-cell-names = "calibration";
+	};