Use the new auto cleanup based locks so error paths are simpler.

While at it, turned a sprintf() call into sysfs_emit().
Signed-off-by: Nuno Sa <nuno.sa@analog.com>
Link: https://patch.msgid.link/20240618-dev-iio-adis-cleanup-v1-4-bd93ce7845c7@analog.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>