loop: update commands in loop_set_status still referring to transfers

The concept of transfers is gone since commit 47e96246 ("block:
remove support for cryptoloop and the xor transfer").

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20250110073750.1582447-3-hch@lst.de


Signed-off-by: Jens Axboe <axboe@kernel.dk>