clk: renesas: mstp: Reformat cpg_mstp_clock_register() for git diff

As the function header of cpg_mstp_clock_register() is split in an
unusual way, "git diff" gets confused when changes to the body of
the function are made, and attributes them to the wrong function.

Reformat the function header to fix this.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Stephen Boyd <sboyd@codeaurora.org>