scsi: smartpqi: turn off lun data caching for ptraid

- allow update the luns for PTRAID devices.

Reviewed-by: Ajish Koshy <ajish.koshy@microsemi.com>
Reviewed-by: Murthy Bhat <murthy.bhat@microsemi.com>
Reviewed-by: Mahesh Rajashekhara <mahesh.rajashekhara@microsemi.com>
Reviewed-by: Justin Lindley <justin.lindley@microsemi.com>
Reviewed-by: Scott Teel <scott.teel@microsemi.com>
Reviewed-by: Kevin Barnett <kevin.barnett@microsemi.com>
Signed-off-by: Dave Carroll <david.carroll@microsemi.com>
Signed-off-by: Don Brace <don.brace@microsemi.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>