NTB: EPF: Fix error code in epf_ntb_bind()

Return an error code if pci_register_driver() fails.  Don't return
success.

Fixes: da51fd247424 ("NTB: EPF: support NTB transfer between PCI RC and EP connection")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Souptick Joarder (HPE) <jrdr.linux@gmail.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>

drivers/pci/endpoint/functions/pci-epf-vntb.c

@@ -1321,7 +1321,8 @@ static int epf_ntb_bind(struct pci_epf *epf)
 	pci_vntb_table[0].vendor = ntb->vntb_vid;
 	pci_vntb_table[0].device = ntb->vntb_pid;
 
-	if (pci_register_driver(&vntb_pci_driver)) {
+	ret = pci_register_driver(&vntb_pci_driver);
+	if (ret) {
 		dev_err(dev, "failure register vntb pci driver\n");
 		goto err_bar_alloc;
 	}