PCI: Decouple IORESOURCE_ROM_ENABLE and PCI_ROM_ADDRESS_ENABLE

Remove the assumption that IORESOURCE_ROM_ENABLE == PCI_ROM_ADDRESS_ENABLE.
PCI_ROM_ADDRESS_ENABLE is the ROM enable bit defined by the PCI spec, so if
we're reading or writing a BAR register value, that's what we should use.
IORESOURCE_ROM_ENABLE is a corresponding bit in struct resource flags.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Gavin Shan <gwshan@linux.vnet.ibm.com>

drivers/pci/probe.c

@@ -227,7 +227,8 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
 			mask64 = (u32)PCI_BASE_ADDRESS_MEM_MASK;
 		}
 	} else {
-		res->flags |= (l & IORESOURCE_ROM_ENABLE);
+		if (l & PCI_ROM_ADDRESS_ENABLE)
+			res->flags |= IORESOURCE_ROM_ENABLE;
 		l64 = l & PCI_ROM_ADDRESS_MASK;
 		sz64 = sz & PCI_ROM_ADDRESS_MASK;
 		mask64 = (u32)PCI_ROM_ADDRESS_MASK;