scsi: mpt3sas: Use high iops queues under some circumstances

The driver will use round-robin method for io submission in batches within
the high iops queues when the number of in-flight ios on the target device
is larger than 8. Otherwise the driver will use low latency reply queues.

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