clk: Improve clk_ops documentation

General:
  - Add parameter names to .round_rate() and .set_rate().

Documentation/clk.txt:
  - Add missing parameter for .set_rate(),
  - Add missing .debug_init().

include/linux/clk-provider.h:
  - Add parent rate documentation for .round_rate(),
  - Reorder documentation to match implementation order,
  - Add missing documentation for .init().

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mike Turquette <mturquette@linaro.org>