iio: locking: introduce __cleanup() based direct mode claiming infrastructure

Allows use of:

       iio_device_claim_direct_scoped(return -EBUSY, indio_dev) {
       }

to automatically call iio_device_release_direct_mode() based on scope.
Typically seen in combination with local device specific locks which
are already have automated cleanup options via guard(mutex)(&st->lock)
and scoped_guard(). Using both together allows most error handling to
be automated.

Reviewed-by: Nuno Sa <nuno.a@analog.com>
Link: https://lore.kernel.org/r/20240128150537.44592-2-jic23@kernel.org


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