ntb: idt: fix error check in ntb_hw_idt.c

idt_create_dev never return NULL and fix smatch warning.
Signed-off-by: Wang Qing <wangqing@vivo.com>
Acked-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>

drivers/ntb/hw/idt/ntb_hw_idt.c

@@ -2511,7 +2511,7 @@ static int idt_init_dbgfs(struct idt_ntb_dev *ndev)
 	/* If the top directory is not created then do nothing */
 	if (IS_ERR_OR_NULL(dbgfs_topdir)) {
 		dev_info(&ndev->ntb.pdev->dev, "Top DebugFS directory absent");
-		return PTR_ERR(dbgfs_topdir);
+		return PTR_ERR_OR_ZERO(dbgfs_topdir);
 	}
 
 	/* Create the info file node */
@@ -2756,7 +2756,7 @@ static int idt_pci_probe(struct pci_dev *pdev,
 
 	/* Allocate the memory for IDT NTB device data */
 	ndev = idt_create_dev(pdev, id);
-	if (IS_ERR_OR_NULL(ndev))
+	if (IS_ERR(ndev))
 		return PTR_ERR(ndev);
 
 	/* Initialize the basic PCI subsystem of the device */