staging: iio: cdc: ad7746: Drop unused i2c_set_clientdata()

As the comment states, this was only used in remove() and now
there is no explicit remove() function to make use of it.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220626122938.582107-10-jic23@kernel.org

drivers/staging/iio/cdc/ad7746.c

@@ -708,8 +708,6 @@ static int ad7746_probe(struct i2c_client *client,
 		return -ENOMEM;
 	chip = iio_priv(indio_dev);
 	mutex_init(&chip->lock);
-	/* this is only used for device removal purposes */
-	i2c_set_clientdata(client, indio_dev);
 
 	chip->client = client;
 	chip->capdac_set = -1;