scsi: aacraid: Fix DMAR issues with iommu=pt

The driver changed the DMA consistent map after consistent memory was
allocated, this invalidated the IOMMU identity mapping. The fix was to
make sure that we set the DMA consistent mask setting once depending on
the controller card.

Signed-off-by: Raghava Aditya Renukunta <RaghavaAditya.Renukunta@microsemi.com>
Reviewed-by: Dave Carroll <david.carroll@microsemi.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>