Merge changes from topic "km/test_hypervisor_retrieve_request"

* changes:
  test(memory share): fragmented hypervisor retrieve request
  feat(memory share): support sending fragmented messages.
  test(memory share): multiple receiver hypervisor retrieve request
  feat(memory share): send multiple receiver regions
  test(memory share): hypervisor retrieve request
  refactor(spm): `ffa_memory_access` constructors
  refactor(ffa_helpers): use bitfields for memory access bitmaps