iio: health: afe4404: Use devm action helper for regulator disable

Use a device lifecycle managed action for regulator disable function.
This helps prevent mistakes like unregistering out of order in cleanup
functions and forgetting to unregister on error paths.

Signed-off-by: Andrew Davis <afd@ti.com>
Link: https://lore.kernel.org/r/20240123140918.215818-3-afd@ti.com


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