cifs: use bvec_set_page to initialize bvecs

Use the bvec_set_page helper to initialize bvecs.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Link: https://lore.kernel.org/r/20230203150634.3199647-14-hch@lst.de


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