iio:adc:ti-ads1015: Improve error reporting for problems during .remove()

Returning an error value in an i2c remove callback results in a generic
error message being emitted by the i2c core, but otherwise it doesn't
make a difference. The device goes away anyhow and the devm cleanups are
called.

So instead of triggering the generic i2c error message, emit a more
helpful message if a problem occurs and return 0 to suppress the generic
message.

This patch is a preparation for making i2c remove callbacks return void.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20220515155929.338656-3-u.kleine-koenig@pengutronix.deSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/ti-ads1015.c

@@ -1098,6 +1098,7 @@ static int ads1015_remove(struct i2c_client *client)
 {
 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
 	struct ads1015_data *data = iio_priv(indio_dev);
+	int ret;
 
 	iio_device_unregister(indio_dev);
 
@@ -1105,7 +1106,12 @@ static int ads1015_remove(struct i2c_client *client)
 	pm_runtime_set_suspended(&client->dev);
 
 	/* power down single shot mode */
-	return ads1015_set_conv_mode(data, ADS1015_SINGLESHOT);
+	ret = ads1015_set_conv_mode(data, ADS1015_SINGLESHOT);
+	if (ret)
+		dev_warn(&client->dev, "Failed to power down (%pe)\n",
+			 ERR_PTR(ret));
+
+	return 0;
 }
 
 #ifdef CONFIG_PM