scsi: lpfc: don't dereference dma_buf->iocbq before null check

From: Colin Ian King <colin.king@canonical.com>

dma_buf->iocbq is being dereferenced immediately before it is
being null checked, so we have a potential null pointer dereference
bug.  Fix this by only dereferencing it only once we have passed
a null check on the pointer.

Detected by CoverityScan, CID#1411652 ("Dereference before null check")

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: James Smart <james.smart@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/lpfc/lpfc_mem.c

@@ -646,7 +646,6 @@ lpfc_sli4_nvmet_alloc(struct lpfc_hba *phba)
 	}
 
 	dma_buf->iocbq = lpfc_sli_get_iocbq(phba);
-	dma_buf->iocbq->iocb_flag = LPFC_IO_NVMET;
 	if (!dma_buf->iocbq) {
 		kfree(dma_buf->context);
 		pci_pool_free(phba->lpfc_drb_pool, dma_buf->dbuf.virt,
@@ -658,6 +657,7 @@ lpfc_sli4_nvmet_alloc(struct lpfc_hba *phba)
 				"2621 Ran out of nvmet iocb/WQEs\n");
 		return NULL;
 	}
+	dma_buf->iocbq->iocb_flag = LPFC_IO_NVMET;
 	nvmewqe = dma_buf->iocbq;
 	wqe = (union lpfc_wqe128 *)&nvmewqe->wqe;
 	/* Initialize WQE */