[$] Designated movable (memory) blocks

The concept of movable memory was initially designed for hot-pluggablememory on server-class systems, but it would now appear that this mechanismis finding a new use in consumer-electronics devices as well. Thedesignated movable block patch set was first submittedby Doug Berger in September 2022. By adding more flexibility around theconfiguration and use of movable memory, this work will, it is hoped, improve howLinux performs on resource-constrained systems.