iio: frequency: adf4350: add missing clk_disable_unprepare() on error in adf4350_probe()

Add the missing clk_disable_unprepare() before return
from adf4350_probe() in the error handling case.
Signed-off-by: NWei Yongjun <yongjun_wei@trendmicro.com.cn>
Reviewed-by: NLars-Peter CLausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

drivers/iio/frequency/adf4350.c

@@ -525,8 +525,10 @@ static int adf4350_probe(struct spi_device *spi)
 	}
 
 	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
-	if (indio_dev == NULL)
-		return -ENOMEM;
+	if (indio_dev == NULL) {
+		ret =  -ENOMEM;
+		goto error_disable_clk;
+	}
 
 	st = iio_priv(indio_dev);