Merge branches 'cpu_topology' and 'mailbox' into juno_mhu_clk_dvfs

Merge branches 'cpu_topology' and 'mailbox' into juno_mhu_clk_dvfs

* cpu_topology:
  arm64: topology: Provide relative power numbers for cores
  arm64: topology: Tell the scheduler about the relative power of cores
  arm64: topology: add MPIDR-based detection
  arm64: topology: Add support for topology DT bindings
  arm64: topology: Initialise default topology state immediately
  arm64: sched: Remove unused mc_capable() and smt_capable()

* mailbox:
  mailbox: Fix deleteing poll timer
  mailbox: Fix TX completion init
  mailbox: pl320: Introduce common API driver
  mailbox: Introduce framework for mailbox
  mailbox: rename pl320-ipc specific mailbox.h