iio: frequency: admv1013: Benefit from devm_clk_get_enabled() to simplify

Make use of devm_clk_get_enabled() to replace some code that effectively
open codes this new function.

To retain ordering move the request to a place that is executed later.
This way the time of enable keeps the same.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20230313185333.2776785-1-u.kleine-koenig@pengutronix.de


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