PCI: Remove unused "res" variable from pci_resource_io()

The "res" variable in pci_resource_io() is never used.  Remove it.
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/pci-sysfs.c

@@ -1211,11 +1211,8 @@ static ssize_t pci_resource_io(struct file *filp, struct kobject *kobj,
 {
 	struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj));
 	int bar = (unsigned long)attr->private;
-	struct resource *res;
 	unsigned long port = off;
 
-	res = &pdev->resource[bar];
-
 	port += pci_resource_start(pdev, bar);
 
 	if (port > pci_resource_end(pdev, bar))