UPSTREAM: mm: multi-gen LRU: section for Bloom filters

Move Bloom filters code into a dedicated section.  Improve the design doc
to explain Bloom filter usage and connection between aging and eviction in
their use.

Link: https://lkml.kernel.org/r/20230118001827.1040870-4-talumbau@google.com


Change-Id: I73e866f687c1ed9f5c8538086aa39408b79897db
Signed-off-by: T.J. Alumbaugh <talumbau@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
(cherry picked from commit ccbbbb85)
Bug: 274865848
Signed-off-by: T.J. Mercier <tjmercier@google.com>