firewire: sbp2: use scsi_dma_(un)map

Use the scsi_dma_map/scsi_dma_unmap helper to simplify the code
a little.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
1 file changed