scsi: a100u2w: switch to generic DMA API

Switch from the legacy PCI DMA API to the generic DMA API.

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