staging: iio: ad7746: add device tree support

Add a of_device_id struct variable and subsequent call to
MODULE_DEVICE_TABLE macro to support device tree.
Signed-off-by: João Seckler <joaoseckler@gmail.com>
Signed-off-by: Lucas Oshiro <lucasseikioshiro@gmail.com>
Co-developed-by: Lucas Oshiro <lucasseikioshiro@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/staging/iio/cdc/ad7746.c

@@ -748,9 +748,19 @@ static const struct i2c_device_id ad7746_id[] = {
 
 MODULE_DEVICE_TABLE(i2c, ad7746_id);
 
+static const struct of_device_id ad7746_of_match[] = {
+	{ .compatible = "adi,ad7745" },
+	{ .compatible = "adi,ad7746" },
+	{ .compatible = "adi,ad7747" },
+	{ },
+};
+
+MODULE_DEVICE_TABLE(of, ad7746_of_match);
+
 static struct i2c_driver ad7746_driver = {
 	.driver = {
 		.name = KBUILD_MODNAME,
+		.of_match_table = ad7746_of_match,
 	},
 	.probe = ad7746_probe,
 	.id_table = ad7746_id,