This series is based on v4.15-rc1 and composed of
scpsys control (PATCH 1-4) and device tree (PATCH 5-6)

changes since v6:
- Rebase to v4.15-rc1.

changes since v5:
- Refine bus protection with proper variable name
  and better implementation for the if statement.

changes since v4:
- Refine scpsys and infracfg for bus protection by passing 
  a boolean flag to determine the register update method

changes since v3:
- Rebase to v4.14-rc1.

changes since v2:
- ensure the clocks used by clocksource driver are registered
  before clocksource init() by using CLK_OF_DECLARE()
- correct the frequency of clk32k/clkrtc_ext/clkrtc_int

changes since v1:
- Rebase to v4.13-next-soc.
- Refine scpsys and infracfg for bus protection.