scsi: aacraid: add fib flag to mark scsi command callback

To correctly identify which fib has a scsi command callback this
patch implements a flag FIB_CONTEXT_FLAG_SCSI_CMD.

Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Raghava Aditya Renukunta <RaghavaAditya.Renukunta@microsemi.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>