dm: use bio_clone_fast in alloc_io/alloc_tio

Replace open coded bio_clone_fast implementations with the actual helper.
Note that the bio allocated as part of the dm_io structure in alloc_io
will only actually be used later in alloc_tio, making this earlier
cloning of the information safe.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220202160109.108149-12-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>