[AGPGART] Fix masking (causes crash on 460GX).

virt_to_page(phys_to_virt(masked_addr)) still works.  But the 460GX
sticks bits in the middle, so the free blows up.

I've tested the agp_allocate_memory() change on Intel 460GX.  I don't have
hardware to test the Intel MCH change, but it looks to me like the same
problem.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Dave Jones <davej@redhat.com>

drivers/char/agp/generic.c

@@ -204,8 +204,7 @@ struct agp_memory *agp_allocate_memory(size_t page_count, u32 type)
 			agp_free_memory(new);
 			return NULL;
 		}
-		new->memory[i] =
-			agp_bridge->driver->mask_memory(virt_to_phys(addr), type);
+		new->memory[i] = virt_to_phys(addr);
 		new->page_count++;
 	}
 

drivers/char/agp/intel-mch-agp.c

@@ -51,7 +51,7 @@ static struct agp_memory *alloc_agpphysmem_i8xx(size_t pg_count, int type)
 	if (new == NULL)
 		return NULL;
 
-	new->memory[0] = agp_bridge->driver->mask_memory(virt_to_phys(addr), type);
+	new->memory[0] = virt_to_phys(addr);
 	new->page_count = 1;
 	new->num_scratch_pages = 1;
 	new->type = AGP_PHYS_MEMORY;