scsi: aacraid: Remove __GFP_DMA for raw srb memory

The raw srb commands do not requires memory that in the ZONE_DMA memory
space. For 32bit srb commands use GFP_DMA32 to limit the memory to 32bit
memory range (4GB).

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>