mm: memcontrol: use generic mod_memcg_page_state for kmem pages

mm: memcontrol: use generic mod_memcg_page_state for kmem pages

The kmem-specific functions do the same thing.  Switch and drop.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Johannes Weiner <[email protected]>
Acked-by: Vladimir Davydov <[email protected]>
Cc: Josef Bacik <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Rik van Riel <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>