Merge changes from topic "ck/mpmm" into integration

* changes:
  docs(maintainers): add Chris Kay to AMU and MPMM
  feat(tc): enable MPMM
  feat(mpmm): add support for MPMM
  feat(amu): enable per-core AMU auxiliary counters
  docs(amu): add AMU documentation
  refactor(amu): refactor enablement and context switching
  refactor(amu): detect auxiliary counters at runtime
  refactor(amu): detect architected counters at runtime
  refactor(amu): conditionally compile auxiliary counter support
  refactor(amu): factor out register accesses
  refactor(amu)!: privatize unused AMU APIs
  refactor(amu)!: remove `PLAT_AMU_GROUP1_COUNTERS_MASK`
  build(amu): introduce ``
  build(fconf)!: clean up source collection
  feat(fdt-wrappers): add CPU enumeration utility function
  build(fdt-wrappers): introduce FDT wrappers makefile
  build(bl2): deduplicate sources
  build(bl1): deduplicate sources