iio: frequency: adf4350: Remove redundant null check before clk_disable_unprepare

Because clk_disable_unprepare() already checked NULL clock parameter,
so the additional check is unnecessary, just remove it.
Signed-off-by: Xu Wang <vulab@iscas.ac.cn>
Link: https://lore.kernel.org/r/20201218094647.1386-1-vulab@iscas.ac.cnSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/frequency/adf4350.c

@@ -582,8 +582,7 @@ static int adf4350_probe(struct spi_device *spi)
 	if (!IS_ERR(st->reg))
 		regulator_disable(st->reg);
 error_disable_clk:
-	if (clk)
-		clk_disable_unprepare(clk);
+	clk_disable_unprepare(clk);
 
 	return ret;
 }
@@ -599,8 +598,7 @@ static int adf4350_remove(struct spi_device *spi)
 
 	iio_device_unregister(indio_dev);
 
-	if (st->clk)
-		clk_disable_unprepare(st->clk);
+	clk_disable_unprepare(st->clk);
 
 	if (!IS_ERR(reg))
 		regulator_disable(reg);