CHROMIUM: mm: multigenerational lru: enable by default

Signed-off-by: Yu Zhao <yuzhao@google.com>

BUG=b:123039911
TEST=Built

Change-Id: Id605eedbc64ebda26789c4960b129520af0cca7c
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/3132028


Tested-by: Yu Zhao <yuzhao@chromium.org>
Commit-Queue: Yu Zhao <yuzhao@chromium.org>
Reviewed-by: Alexandre Marciano Gimenez <raging@google.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>