stmmac: pci: use defined constant instead of magic number

The last standard PCI resource is defined as PCI_STD_RESOURCE_END. Thus, we
could use it instead of plain integer.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/stmmac_pci.c

@@ -90,7 +90,7 @@ static int stmmac_pci_probe(struct pci_dev *pdev,
 	}
 
 	/* Get the base address of device */
-	for (i = 0; i <= 5; i++) {
+	for (i = 0; i <= PCI_STD_RESOURCE_END; i++) {
 		if (pci_resource_len(pdev, i) == 0)
 			continue;
 		addr = pci_iomap(pdev, i, 0);