Merge changes from topic "ja/notifications"

* changes:
  test(ff-a): signaling per-vCPU notifications (SP to VM)
  test(ff-a): signaling per-vCPU notifications
  refactor(spm): helper functions for SPM's MP tests
  test(ff-a): FFA_NOTIFICATION_INFO_GET interface
  feat(ff-a): FFA_NOTIFICATION_INFO_GET helpers