mm: swap: fix vmstats for huge pages

Many of the callbacks called by pagevec_lru_move_fn() does not correctly
update the vmstats for huge pages. Fix that. Also __pagevec_lru_add_fn()
use the irq-unsafe alternative to update the stat as the irqs are
already disabled.

Signed-off-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Link: http://lkml.kernel.org/r/20200527182916.249910-1-shakeelb@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>