NIU: fix incorrect error return, missed in previous revert

Commit 7930742, reverting 26fd962, missed out on reverting an incorrect
change to a return value.  The niu_pci_vpd_scan_props(..) == 1 case appears
to be a normal path - treating it as an error and return -EINVAL was
breaking VPD_SCAN and causing the driver to fail to load.

Fix, so my Neptune card works again.

Cc: Kangjie Lu <[email protected]>
Cc: Shannon Nelson <[email protected]>
Cc: David S. Miller <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: stable <[email protected]>
Fixes: 7930742 ('Revert "niu: fix missing checks of niu_pci_eeprom_read"')
Signed-off-by: Paul Jakma <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

Author: pjakma

drivers/net/ethernet/sun/niu.c

@@ -8191,8 +8191,9 @@ static int niu_pci_vpd_fetch(struct niu *np, u32 start)
 		err = niu_pci_vpd_scan_props(np, here, end);
 		if (err < 0)
 			return err;
+		/* ret == 1 is not an error */
 		if (err == 1)
-			return -EINVAL;
+			return 0;
 	}
 	return 0;
 }