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

drivers/iio/frequency/adf4350.c

···
 	if (!IS_ERR(st->reg))
 		regulator_disable(st->reg);
 error_disable_clk:
-	if (clk)
-		clk_disable_unprepare(clk);
+	clk_disable_unprepare(clk);
 
 	return ret;
 }
···
 
 	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);