agp: don't lock pages

AGP should not need to lock pages. They are not protecting any race
because there is no lock_page calls, only SetPageLocked.

This is causing hangs with d00806b183.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/char/agp/sgi-agp.c

@@ -51,7 +51,6 @@ static void *sgi_tioca_alloc_page(struct agp_bridge_data *bridge)
 		return NULL;
 
 	get_page(page);
-	SetPageLocked(page);
 	atomic_inc(&agp_bridge->current_memory_agp);
 	return page_address(page);
 }