clk: renesas: rcar-gen3: Grammar s/dependent of/dependent on/

Fix grammar in comments for cpg_z_clk_set_rate().

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/20210326120100.1577596-5-geert+renesas@glider.be