iio: potentiometer: ds1803: Convert enum->pointer for data in the ID table

Convert enum->pointer for data in the ID table, so that
device_get_match_data() can do match against OF/ACPI/I2C tables, once i2c
bus type match support added to it.

Replace enum->struct *ds1803_cfg for data in the ID table and simplify
ds1803_probe() by replacing device_get_match_data() with
i2c_get_match_data().
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230812144106.163355-1-biju.das.jz@bp.renesas.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/potentiometer/ds1803.c

@@ -204,7 +204,6 @@ static const struct iio_info ds1803_info = {
 
 static int ds1803_probe(struct i2c_client *client)
 {
-	const struct i2c_device_id *id = i2c_client_get_device_id(client);
 	struct device *dev = &client->dev;
 	struct ds1803_data *data;
 	struct iio_dev *indio_dev;
@@ -217,9 +216,7 @@ static int ds1803_probe(struct i2c_client *client)
 
 	data = iio_priv(indio_dev);
 	data->client = client;
-	data->cfg = device_get_match_data(dev);
-	if (!data->cfg)
-		data->cfg = &ds1803_cfg[id->driver_data];
+	data->cfg = i2c_get_match_data(client);
 
 	indio_dev->info = &ds1803_info;
 	indio_dev->channels = data->cfg->channels;
@@ -239,10 +236,10 @@ static const struct of_device_id ds1803_dt_ids[] = {
 MODULE_DEVICE_TABLE(of, ds1803_dt_ids);
 
 static const struct i2c_device_id ds1803_id[] = {
-	{ "ds1803-010", DS1803_010 },
-	{ "ds1803-050", DS1803_050 },
-	{ "ds1803-100", DS1803_100 },
-	{ "ds3502", DS3502 },
+	{ "ds1803-010", (kernel_ulong_t)&ds1803_cfg[DS1803_010] },
+	{ "ds1803-050", (kernel_ulong_t)&ds1803_cfg[DS1803_050] },
+	{ "ds1803-100", (kernel_ulong_t)&ds1803_cfg[DS1803_100] },
+	{ "ds3502", (kernel_ulong_t)&ds1803_cfg[DS3502] },
 	{}
 };
 MODULE_DEVICE_TABLE(i2c, ds1803_id);