scsi: qla2xxx: Enable Target Multi Queue

Enable Multi Queue for Target mode. At Initiator LUN scan time, each LUN
is assign to a QPair. Each QPair is affinitize to certain CPU. When new
cmd arrives from the wire, the lunid is used to search for qpair. The
qpair's affinitized cpuid will be used to queue up the work element.

Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>