iio: adc: ad7780: Fix a resource handling path in 'ad7780_probe()'

If 'ad7780_init_gpios()' fails, we must not release some resources that
have not been allocated yet. Return directly instead.

Fixes: 5bb30e7 ("staging: iio: ad7780: move regulator to after GPIO init")
Fixes: 9085daa ("staging: iio: ad7780: add gain & filter gpio support")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: Renato Lui Geh <renatogeh@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/ad7780.c

@@ -329,7 +329,7 @@ static int ad7780_probe(struct spi_device *spi)
 
 	ret = ad7780_init_gpios(&spi->dev, st);
 	if (ret)
-		goto error_cleanup_buffer_and_trigger;
+		return ret;
 
 	st->reg = devm_regulator_get(&spi->dev, "avdd");
 	if (IS_ERR(st->reg))