scsi: mpt3sas: Introduce Base function for cloning.

All scsi IO's and config request's data buffer and sgl are cloned to
system memory in _clone_sg_entries before submitting it to firmware.

Signed-off-by: Suganath Prabu S <suganath-prabu.subramani@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>