PCI: Don't assign or reassign immutable resources

IORESOURCE_PCI_FIXED means the resource can't be moved, so if it's set,
don't bother trying to assign or reassign the resource.

Signed-off-by: Bjorn Helgaas <[e-mail]>

drivers/pci/setup-res.c

···
 	resource_size_t align, size;
 	int ret;
 
+	if (res->flags & IORESOURCE_PCI_FIXED)
+		return 0;
+
 	res->flags |= IORESOURCE_UNSET;
 	align = pci_resource_alignment(dev, res);
 	if (!align) {
···
 	unsigned long flags;
 	resource_size_t new_size;
 	int ret;
+
+	if (res->flags & IORESOURCE_PCI_FIXED)
+		return 0;
 
 	flags = res->flags;
 	res->flags |= IORESOURCE_UNSET;