mm/memcontrol.c: fix defined but not used compiler warning

test_mem_cgroup_node_reclaimable() is used only when MAX_NUMNODES > 1, so
move it into the compiler if statement

[akpm@linux-foundation.org: clean up layout]
Signed-off-by: Michele Curti <michele.curti@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/memcontrol.c

@@ -1616,6 +1616,8 @@ static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
 			 NULL, "Memory cgroup out of memory");
 }
 
+#if MAX_NUMNODES > 1
+
 /**
  * test_mem_cgroup_node_reclaimable
  * @memcg: the target memcg
@@ -1638,7 +1640,6 @@ static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *memcg,
 	return false;
 
 }
-#if MAX_NUMNODES > 1
 
 /*
  * Always updating the nodemask is not very good - even if we have an empty