ASoC: sgtl5000: add device tree probe support

It adds device tree probe support for sgtl5000 driver.
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Liam Girdwood <lrg@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

Documentation/devicetree/bindings/sound/soc/codecs/fsl-sgtl5000.txt

+* Freescale SGTL5000 Stereo Codec
+
+Required properties:
+- compatible : "fsl,sgtl5000".
+
+Example:
+
+codec: sgtl5000@0a {
+	compatible = "fsl,sgtl5000";
+	reg = <0x0a>;
+};

sound/soc/codecs/sgtl5000.c

@@ -20,6 +20,7 @@
 #include <linux/regulator/driver.h>
 #include <linux/regulator/machine.h>
 #include <linux/regulator/consumer.h>
+#include <linux/of_device.h>
 #include <sound/core.h>
 #include <sound/tlv.h>
 #include <sound/pcm.h>
@@ -1494,10 +1495,17 @@ static const struct i2c_device_id sgtl5000_id[] = {
 
 MODULE_DEVICE_TABLE(i2c, sgtl5000_id);
 
+static const struct of_device_id sgtl5000_dt_ids[] = {
+	{ .compatible = "fsl,sgtl5000", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(i2c, sgtl5000_dt_ids);
+
 static struct i2c_driver sgtl5000_i2c_driver = {
 	.driver = {
 		   .name = "sgtl5000",
 		   .owner = THIS_MODULE,
+		   .of_match_table = sgtl5000_dt_ids,
 		   },
 	.probe = sgtl5000_i2c_probe,
 	.remove = __devexit_p(sgtl5000_i2c_remove),