iio: potentiometer: merge calls to of_match_device and of_device_get_match_data

Drop call to of_match_device, which is subsumed by the subsequent
call to of_device_get_match_data.  The code becomes simpler, and a
temporary variable can be dropped.

The semantic match that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r@
local idexpression match;
identifier i;
expression x, dev, e, e1;
@@
-        match@i = of_match_device(x, dev);
-        if (match) e = of_device_get_match_data(dev);
-        else e = e1;
+        e = of_device_get_match_data(dev);
+        if (!e) e = e1;

@@
identifier r.i;
@@
- const struct of_device_id *i;
... when != i
// </smpl>
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Reviewed-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/potentiometer/max5481.c

@@ -137,7 +137,6 @@ static int max5481_probe(struct spi_device *spi)
 	struct iio_dev *indio_dev;
 	struct max5481_data *data;
 	const struct spi_device_id *id = spi_get_device_id(spi);
-	const struct of_device_id *match;
 	int ret;
 
 	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*data));
@@ -149,10 +148,8 @@ static int max5481_probe(struct spi_device *spi)
 
 	data->spi = spi;
 
-	match = of_match_device(of_match_ptr(max5481_match), &spi->dev);
-	if (match)
 	data->cfg = of_device_get_match_data(&spi->dev);
-	else
+	if (!data->cfg)
 		data->cfg = &max5481_cfg[id->driver_data];
 
 	indio_dev->name = id->name;

drivers/iio/potentiometer/mcp4018.c

@@ -147,7 +147,6 @@ static int mcp4018_probe(struct i2c_client *client)
 	struct device *dev = &client->dev;
 	struct mcp4018_data *data;
 	struct iio_dev *indio_dev;
-	const struct of_device_id *match;
 
 	if (!i2c_check_functionality(client->adapter,
 				     I2C_FUNC_SMBUS_BYTE)) {
@@ -162,10 +161,8 @@ static int mcp4018_probe(struct i2c_client *client)
 	i2c_set_clientdata(client, indio_dev);
 	data->client = client;
 
-	match = of_match_device(of_match_ptr(mcp4018_of_match), dev);
-	if (match)
 	data->cfg = of_device_get_match_data(dev);
-	else
+	if (!data->cfg)
 		data->cfg = &mcp4018_cfg[i2c_match_id(mcp4018_id, client)->driver_data];
 
 	indio_dev->dev.parent = dev;

drivers/iio/potentiometer/mcp4531.c

@@ -360,7 +360,6 @@ static int mcp4531_probe(struct i2c_client *client)
 	struct device *dev = &client->dev;
 	struct mcp4531_data *data;
 	struct iio_dev *indio_dev;
-	const struct of_device_id *match;
 
 	if (!i2c_check_functionality(client->adapter,
 				     I2C_FUNC_SMBUS_WORD_DATA)) {
@@ -375,10 +374,8 @@ static int mcp4531_probe(struct i2c_client *client)
 	i2c_set_clientdata(client, indio_dev);
 	data->client = client;
 
-	match = of_match_device(of_match_ptr(mcp4531_of_match), dev);
-	if (match)
 	data->cfg = of_device_get_match_data(dev);
-	else
+	if (!data->cfg)
 		data->cfg = &mcp4531_cfg[i2c_match_id(mcp4531_id, client)->driver_data];
 
 	indio_dev->dev.parent = dev;