ASoC: ssm2602: add device tree bindings

Allow the ssm2602/ssm2603/ssm2604 codec driver to be
instantiated from the device tree.

Also, add Kconfig prompts to allow manual selection of both the
I2C and SPI configuration versions of the driver.

Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
diff --git a/sound/soc/codecs/ssm2602-spi.c b/sound/soc/codecs/ssm2602-spi.c
index 2bf55e2..b5df14f 100644
--- a/sound/soc/codecs/ssm2602-spi.c
+++ b/sound/soc/codecs/ssm2602-spi.c
@@ -26,10 +26,17 @@
 	return 0;
 }
 
+static const struct of_device_id ssm2602_of_match[] = {
+	{ .compatible = "adi,ssm2602", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, ssm2602_of_match);
+
 static struct spi_driver ssm2602_spi_driver = {
 	.driver = {
 		.name	= "ssm2602",
 		.owner	= THIS_MODULE,
+		.of_match_table = ssm2602_of_match,
 	},
 	.probe		= ssm2602_spi_probe,
 	.remove		= ssm2602_spi_remove,