staging: iio: resolver: replace iio_device_register by devm_iio_device_register

Use devm_iio_device_register instead of iio_device_register when the remove
function is only used to call iio_device_unregister in order to ease the error path.
Since resource managed functions implicitly call unregister at driver detach also remove
iio_device_unregister
Signed-off-by: NIoana Ciornei <ciorneiioana@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/iio/resolver/ad2s90.c

@@ -79,7 +79,7 @@ static int ad2s90_probe(struct spi_device *spi)
 	indio_dev->num_channels = 1;
 	indio_dev->name = spi_get_device_id(spi)->name;
 
-	ret = iio_device_register(indio_dev);
+	ret = devm_iio_device_register(indio_dev->dev.parent, indio_dev);
 	if (ret)
 		return ret;
 
@@ -91,13 +91,6 @@ static int ad2s90_probe(struct spi_device *spi)
 	return 0;
 }
 
-static int ad2s90_remove(struct spi_device *spi)
-{
-	iio_device_unregister(spi_get_drvdata(spi));
-
-	return 0;
-}
-
 static const struct spi_device_id ad2s90_id[] = {
 	{ "ad2s90" },
 	{}
@@ -110,7 +103,6 @@ static struct spi_driver ad2s90_driver = {
 		.owner = THIS_MODULE,
 	},
 	.probe = ad2s90_probe,
-	.remove = ad2s90_remove,
 	.id_table = ad2s90_id,
 };
 module_spi_driver(ad2s90_driver);