mm: memcontrol: switch to the updated jump-label API

According to <linux/jump_label.h> the direct use of struct static_key is
deprecated.  Update the socket and slab accounting code accordingly.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: David S. Miller <davem@davemloft.net>
Reported-by: Jason Baron <jbaron@akamai.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>