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/include/linux/ioport.h b/include/linux/ioport.h
index f4195de..4a81189 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -121,7 +121,7 @@
 			     resource_size_t size, resource_size_t min,
 			     resource_size_t max, resource_size_t align,
 			     resource_size_t (*alignf)(void *,
-						       struct resource *,
+						       const struct resource *,
 						       resource_size_t,
 						       resource_size_t),
 			     void *alignf_data);