scsi: smartpqi: correct bdma hw bug

add workaround for BDMA hardware bug that can cause
hw to read up to 12 SGL elements (192 bytes) beyond the
last element in the list. This fix avoids IOMMU violations

Reviewed-by: Scott Benesh <scott.benesh@microsemi.com>
Signed-off-by: Kevin Barnett <kevin.barnett@microsemi.com>
Signed-off-by: Don Brace <don.brace@microsemi.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>