k3S HV: Fix some races in starting secondary threads
  KVM: PPC: Book3S HV: Allow KVM guests to stop secondary threads coming online
  PPC: ePAPR: Convert header to uapi
  KVM: PPC: Move mtspr/mfspr emulation into own functions
  KVM: Documentation: Fix reentry-to-be-consistent paragraph
  KVM: PPC: 44x: fix DCR read/write