[PATCH -next] iio: adc: ad7793: Add missing error code in ad7793_setup()

[YueHaibing]

Set error code while device ID query failed.

Fixes: 88bc30548aae ("IIO: ADC: New driver for AD7792/AD7793 3 Channel SPI ADC")
Signed-off-by: YueHaibing <yuehaibing@xxxxxxxxxx>
---
 drivers/iio/adc/ad7793.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/iio/adc/ad7793.c b/drivers/iio/adc/ad7793.c
index 5e980a06258e..b4f9ac3838e1 100644
--- a/drivers/iio/adc/ad7793.c
+++ b/drivers/iio/adc/ad7793.c
@@ -279,6 +279,7 @@ static int ad7793_setup(struct iio_dev *indio_dev,
 	id &= AD7793_ID_MASK;
 
 	if (id != st->chip_info->id) {
+		ret = -EINVAL;
 		dev_err(&st->sd.spi->dev, "device ID query failed\n");
 		goto out;
 	}
-- 
2.17.1