iio:ti-ads1015: fix a wrong pointer definition.

The call to i2c_get_clientdata(client) returns a struct iio_dev*, not
the needed struct ads1015_data*. We need here an intermediate step as
in the function: void ads1015_get_channels_config(struct i2c_client *client).

Signed-off-by: Giorgio Dal Molin <giorgio.nicole@arcor.de>
Fixes: ecc24e7 ("iio: adc: Add TI ADS1015 ADC driver support")
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/adc/ti-ads1015.c

@@ -489,7 +489,8 @@ static struct iio_info ads1115_info = {
 #ifdef CONFIG_OF
 static int ads1015_get_channels_config_of(struct i2c_client *client)
 {
-	struct ads1015_data *data = i2c_get_clientdata(client);
+	struct iio_dev *indio_dev = i2c_get_clientdata(client);
+	struct ads1015_data *data = iio_priv(indio_dev);
 	struct device_node *node;
 
 	if (!client->dev.of_node ||