mm/memcontrol.c: make local symbol static

Fix the following sparse warning:

  mm/memcontrol.c:1097:14: warning: symbol 'memcg1_stats' was not declared. Should it be static?

Link: http://lkml.kernel.org/r/20180118193327.14200-1-chrisadr@gentoo.orgSigned-off-by: Christopher Díaz Riveros <chrisadr@gentoo.org>
Cc: Michal Hocko <mhocko@kernel.org>
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

@@ -1095,7 +1095,7 @@ static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg)
 	return false;
 }
 
-unsigned int memcg1_stats[] = {
+static const unsigned int memcg1_stats[] = {
 	MEMCG_CACHE,
 	MEMCG_RSS,
 	MEMCG_RSS_HUGE,