iio: adc: ad7124: Silence no spi_device_id warnings

SPI devices use the spi_device_id for module autoloading even on
systems using device tree, after commit 5fa6863ba692 ("spi: Check
we have a spi_device_id for each DT compatible"), kernel warns as
follows since the spi_device_id is missing:

SPI driver ad7124 has no spi_device_id for adi,ad7124-4
SPI driver ad7124 has no spi_device_id for adi,ad7124-8

Add spi_device_id entries to silence the warnings, and ensure driver
module autoloading works.

Signed-off-by: Wei Yongjun <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jonathan Cameron <[e-mail]>

drivers/iio/adc/ad7124.c

···
 
 	info = of_device_get_match_data(&spi->dev);
 	if (!info)
+		info = (void *)spi_get_device_id(spi)->driver_data;
+	if (!info)
 		return -ENODEV;
 
 	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
···
 };
 MODULE_DEVICE_TABLE(of, ad7124_of_match);
 
+static const struct spi_device_id ad71124_ids[] = {
+	{ "ad7124-4", (kernel_ulong_t)&ad7124_chip_info_tbl[ID_AD7124_4] },
+	{ "ad7124-8", (kernel_ulong_t)&ad7124_chip_info_tbl[ID_AD7124_8] },
+	{}
+};
+MODULE_DEVICE_TABLE(spi, ad71124_ids);
+
 static struct spi_driver ad71124_driver = {
 	.driver = {
 		.name = "ad7124",
 		.of_match_table = ad7124_of_match,
 	},
 	.probe = ad7124_probe,
+	.id_table = ad71124_ids,
 };
 module_spi_driver(ad71124_driver);