scsi: lpfc: Fix lingering lpfc_wq resource after driver unload

After driver unloads, lpfc_wq remains active. The destroy_workqueue
calls were not being made in driver unload.  Additionally, SLI3 is
allocating lpfc_wq resources, but never uses it.

Make the destroy_workqueue calls on driver unload.  Modify the SLI3 code
path no longer allocate lpfc_wq resources.
Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <james.smart@broadcom.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/lpfc/lpfc_init.c

@@ -6420,8 +6420,11 @@ lpfc_setup_driver_resource_phase2(struct lpfc_hba *phba)
 		return error;
 	}
 
-	/* workqueue for deferred irq use */
+	/* The lpfc_wq workqueue for deferred irq use, is only used for SLI4 */
+	if (phba->sli_rev == LPFC_SLI_REV4)
 		phba->wq = alloc_workqueue("lpfc_wq", WQ_MEM_RECLAIM, 0);
+	else
+		phba->wq = NULL;
 
 	return 0;
 }
@@ -6444,6 +6447,7 @@ lpfc_unset_driver_resource_phase2(struct lpfc_hba *phba)
 	}
 
 	/* Stop kernel worker thread */
+	if (phba->worker_thread)
 		kthread_stop(phba->worker_thread);
 }
 
@@ -11727,6 +11731,7 @@ lpfc_pci_remove_one_s4(struct pci_dev *pdev)
 	lpfc_nvme_free(phba);
 	lpfc_free_iocb_list(phba);
 
+	lpfc_unset_driver_resource_phase2(phba);
 	lpfc_sli4_driver_resource_unset(phba);
 
 	/* Unmap adapter Control and Doorbell registers */