Merge branch 'working-hikey-tracking-optee-v4.4' into working-hikey-mainline-rebase-v4.4-c30

* working-hikey-tracking-optee-v4.4:
  tee: add kernel internal client interface **not for mainline**
  Documentation: tee subsystem and op-tee driver
  tee: add OP-TEE driver
  tee: generic TEE subsystem
  dt/bindings: add bindings for optee
  ARM: 8481/2: drivers: psci: replace psci firmware calls
  ARM: 8480/2: arm64: add implementation for arm-smccc
  ARM: 8479/2: add implementation for arm-smccc
  ARM: 8478/2: arm/arm64: add arm-smccc