memcg: Kconfig info update

Now there are only 2 members in struct page_cgroup.  Update config MEMCG
description accordingly.

Signed-off-by: Sergey Dyasly <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Acked-by: KOSAKI Motohiro <[email protected]>
Acked-by: Johannes Weiner <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Author: Sergey Dyasly

init/Kconfig

@@ -899,7 +899,7 @@ config MEMCG
 
 	  Note that setting this option increases fixed memory overhead
 	  associated with each page of memory in the system. By this,
-	  20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
+	  8(16)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
 	  usage tracking struct at boot. Total amount of this is printed out
 	  at boot.