Merge branch 'scif-clk-sck-brg-for-v4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-drivers into tty-next

Geert writes:

Summary:
  - Clean up the naming of clocks in the sh-sci driver and its DT bindings,
  - Add support for the optional external clock on (H)SCI(F), where this pin
    can serve as a clock input,
  - Add support for the optional clock sources for the Baud Rate
    Generator for External Clock (BRG), as found on some SCIF variants
    and on HSCIF.