resource/PCI: mark struct resource as const

Now that we return the new resource start position, there is no
need to update "struct resource" inside the align function.
Therefore, mark the struct resource as const.

Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
diff --git a/arch/xtensa/kernel/pci.c b/arch/xtensa/kernel/pci.c
index d7efab0..cd10269 100644
--- a/arch/xtensa/kernel/pci.c
+++ b/arch/xtensa/kernel/pci.c
@@ -70,8 +70,8 @@
  * which might have be mirrored at 0x0100-0x03ff..
  */
 resource_size_t
-pcibios_align_resource(void *data, struct resource *res, resource_size_t size,
-    		       resource_size_t align)
+pcibios_align_resource(void *data, const struct resource *res,
+		       resource_size_t size, resource_size_t align)
 {
 	struct pci_dev *dev = data;
 	resource_size_t start = res->start;