iio: adc: aspeed: set driver data when adc probe.

Fix the issue when adc remove will get the null driver data.

Fixed: commit 57380323 ("iio: Aspeed ADC")
Signed-off-by: Billy Tsai <billy_tsai@aspeedtech.com>
Link: https://lore.kernel.org/r/20210831071458.2334-2-billy_tsai@aspeedtech.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/aspeed_adc.c

@@ -183,6 +183,7 @@ static int aspeed_adc_probe(struct platform_device *pdev)
 
 	data = iio_priv(indio_dev);
 	data->dev = &pdev->dev;
+	platform_set_drvdata(pdev, indio_dev);
 
 	data->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(data->base))