sata_via: restore vt*_prepare_host error handling

commit b9d5b89b (sata_via: fix support
for 5287) accidently (?) removed vt*_prepare_host error handling - restore it

catched by gcc:
drivers/ata/sata_via.c: In function 'svia_init_one':
drivers/ata/sata_via.c:567: warning: 'host' may be used uninitialized in this function
Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Joseph Chan <JosephChan@via.com.tw>
Cc: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/ata/sata_via.c

@@ -602,8 +602,10 @@ static int svia_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 		rc = vt8251_prepare_host(pdev, &host);
 		break;
 	default:
-		return -EINVAL;
+		rc = -EINVAL;
 	}
+	if (rc)
+		return rc;
 
 	svia_configure(pdev);