scsi: fnic: Remove unneeded flush_workqueue()

All work currently pending will be done first by calling
destroy_workqueue(). There is no need to flush it explicitly.

Link: https://lore.kernel.org/r/20220424065406.3228528-1-ran.jianping@zte.com.cnReported-by: NZeal Robot <zealci@zte.com.cn>
Signed-off-by: Nran jianping <ran.jianping@zte.com.cn>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/fnic/fnic_main.c

@@ -1146,10 +1146,8 @@ static void __exit fnic_cleanup_module(void)
 {
 	pci_unregister_driver(&fnic_driver);
 	destroy_workqueue(fnic_event_queue);
-	if (fnic_fip_queue) {
-		flush_workqueue(fnic_fip_queue);
+	if (fnic_fip_queue)
 		destroy_workqueue(fnic_fip_queue);
-	}
 	kmem_cache_destroy(fnic_sgl_cache[FNIC_SGL_CACHE_MAX]);
 	kmem_cache_destroy(fnic_sgl_cache[FNIC_SGL_CACHE_DFLT]);
 	kmem_cache_destroy(fnic_io_req_cache);