s390/pci: PCI function group 0 is valid for clp_query_pci_fn

The PCI function group 0 is a valid function group,
it is wrong to reject it.

Let's accept PCI function group 0.
Signed-off-by: NPierre Morel <pmorel@linux.vnet.ibm.com>
Acked-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/pci/pci_clp.c

@@ -176,8 +176,7 @@ static int clp_query_pci_fn(struct zpci_dev *zdev, u32 fh)
 		rc = clp_store_query_pci_fn(zdev, &rrb->response);
 		if (rc)
 			goto out;
-		if (rrb->response.pfgid)
-			rc = clp_query_pci_fngrp(zdev, rrb->response.pfgid);
+		rc = clp_query_pci_fngrp(zdev, rrb->response.pfgid);
 	} else {
 		zpci_err("Q PCI FN:\n");
 		zpci_err_clp(rrb->response.hdr.rsp, rc);