iio: adc: rockchip_saradc: Make use of devm_clk_get_enabled

Use devm_clk_get_enabled() to avoid manually disabling the
clock.

Signed-off-by: Shreeya Patel <shreeya.patel@collabora.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20230603185340.13838-4-shreeya.patel@collabora.com


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>