scsi: aha1542: Use memcpy_{from,to}_bvec()

Use the memcpy_{from,to}_bvec() helpers instead of open coding them.

Link: https://lore.kernel.org/r/20211018060802.1815982-1-hch@lst.de


Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>