ASoC: ALC5632: Add device tree binding documentation

Document the device tree binding for the ALC5632 codec and update vendor
specific prefix for the Realtek.
Signed-off-by: Leon Romanovsky <leon@leon.nu>
Acked-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

Documentation/devicetree/bindings/sound/alc5632.txt

+ALC5632 audio CODEC
+
+This device supports I2C only.
+
+Required properties:
+
+  - compatible : "realtek,alc5632"
+
+  - reg : the I2C address of the device.
+
+  - gpio-controller : Indicates this device is a GPIO controller.
+
+  - #gpio-cells : Should be two. The first cell is the pin number and the
+    second cell is used to specify optional parameters (currently unused).
+
+Example:
+
+alc5632: alc5632@1e {
+	compatible = "realtek,alc5632";
+	reg = <0x1a>;
+
+	gpio-controller;
+	#gpio-cells = <2>;
+};

Documentation/devicetree/bindings/vendor-prefixes.txt

@@ -33,6 +33,7 @@ nxp	NXP Semiconductors
 powervr	Imagination Technologies
 qcom	Qualcomm, Inc.
 ramtron	Ramtron International
+realtek Realtek Semiconductor Corp.
 samsung	Samsung Semiconductor
 sbs	Smart Battery System
 schindler	Schindler