Fix command timeout caused by data underrun during fetching ATAPI sense
data, introduced by r246713. There are two places where ata_request is
filled in ATA_CAM: ata_cam_begin_transaction() and ata_cam_request_sense().
In the first case DMA should be done for addresses from the CCB. In second
case, DMA should be done to the different address, the address of the sense
buffer inside the CCB structure itself.