scsi: hisi_sas: fix a typo in hisi_sas_task_prep()

Fix a typo in hisi_sas_task_prep().

Fixes: 7eee4b92 ("scsi: hisi_sas: relocate smp sg map")
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/hisi_sas/hisi_sas_main.c

@@ -390,7 +390,7 @@ static int hisi_sas_task_prep(struct sas_task *task,
 			}
 			n_elem_resp = dma_map_sg(dev, &task->smp_task.smp_resp,
 						 1, DMA_FROM_DEVICE);
-			if (!n_elem_req) {
+			if (!n_elem_resp) {
 				rc = -ENOMEM;
 				goto err_out_dma_unmap;
 			}