iio: proximity: sx9324: Use automated cleanup for locks and IIO mode claiming.

This simplifies error handling paths and generallly removes a bunch
of boilerplate.

Reviewed-by: Nuno Sa <nuno.a@analog.com>
Link: https://lore.kernel.org/r/20240128150537.44592-8-jic23@kernel.org


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