scsi: megaraid_sas: Add support for MPI toolbox commands

Added driver support to allow passthrough MPI toolbox type MFI commands to
firmware based on firmware capability.

Signed-off-by: Sumit Saxena <sumit.saxena@broadcom.com>
Signed-off-by: Chandrakanth Patil <chandrakanth.patil@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>