dasd: use bvec_virt

Use bvec_virt instead of open coding it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20210804095634.460779-14-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 files changed