agp: Switch mask_memory() method to take address argument again, not page

In commit 07613ba2 ("agp: switch AGP to use page array instead of
unsigned long array") we switched the mask_memory() method to take a
'struct page *' instead of an address. This is painful, because in some
cases it has to be an IOMMU-mapped virtual bus address (in fact,
shouldn't it _always_ be a dma_addr_t returned from pci_map_xxx(), and
we just happen to get lucky most of the time?)

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/drivers/char/agp/sgi-agp.c b/drivers/char/agp/sgi-agp.c
index d3ea2e4..0d47fa8 100644
--- a/drivers/char/agp/sgi-agp.c
+++ b/drivers/char/agp/sgi-agp.c
@@ -70,10 +70,9 @@
  * entry.
  */
 static unsigned long
-sgi_tioca_mask_memory(struct agp_bridge_data *bridge,
-		      struct page *page, int type)
+sgi_tioca_mask_memory(struct agp_bridge_data *bridge, dma_addr_t addr,
+		      int type)
 {
-	unsigned long addr = phys_to_gart(page_to_phys(page));
 	return tioca_physpage_to_gart(addr);
 }
 
@@ -190,7 +189,8 @@
 
 	for (i = 0, j = pg_start; i < mem->page_count; i++, j++) {
 		table[j] =
-		    bridge->driver->mask_memory(bridge, mem->pages[i],
+		    bridge->driver->mask_memory(bridge,
+						phys_to_gart(page_to_phys(mem->pages[i])),
 						mem->type);
 	}