Revert "CHROMIUM: mm: Fix calculation of dirtyable memory"

This reverts commit 605508d96608de30b8053f8bfa4f3bcee1b8c462.
Revert "mm, zswap: Fix CPU hotplug callback registration"

This reverts commit 8b6e2a0c590dfb68baccaf90ebd18c8a23d07a9d.
Fix build mmap