Revert "CHROMIUM: Add implementation of MGLRU in sysfs"

This reverts commit 5d074cc3.

Reason for revert: memcg bug and buffer overflow

Original change's description:
> CHROMIUM: Add implementation of MGLRU in sysfs
>
> debugfs is disabled by default for security reasons. This CL removes the
> dependency of lru_gen on debug and adds new implemenetation using sysfs.
> Path changes from /sys/kernel/debug/lru_gen to /sys/kernel/mm/lru_gen/admin
>
> BUG=b:241321277
> TEST=Manual testing on DUT
> TEST=cat /sys/kernel/mm/lru_gen/admin && /sys/kernel/debug/lru_gen
> TEST=same result before and after dropping the pages
>
> Signed-off-by: Bryan Yu <yuholong@google.com>
> Change-Id: I62d8cbd4b8b614dbe6da08c4a11d7c99e30bb5ac
> Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/3839069


> Reviewed-by: Yu Zhao <yuzhao@chromium.org>
> Reviewed-by: Suleiman Souhlal <suleiman@chromium.org>

Bug: b:241321277
Change-Id: I53c45bf1a94fc540d3974876f4eff2fbb6c8b3fb
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/3960194


Reviewed-by: Yu Zhao <yuzhao@chromium.org>
Commit-Queue: Bryan Yu <yuholong@google.com>
Tested-by: Bryan Yu <yuholong@google.com>