scsi: qla2xxx: Skip IRQ affinity for Target QPairs

Fix co-existence between Block MQ and Target Mode. Block MQ and
initiator mode requires midlayer queue mapping to check for IRQ to be
affinitized. For target mode, it's not the case.

Fixes: 09620eeb ("scsi: qla2xxx: Add debug knob for user control workload")
Cc: <stable@vger.kernel.org> # 4.12+
Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>