clk: renesas: rcar-gen4: Add support for fractional multiplication

R-Car Gen4 PLLs support fractional multiplication, which can improve
accuracy when configuring a specific frequency.

Add support for fractional multiplication to the custom clock driver
for PLLs, which is currently used only for PLL2 on R-Car V4H.
While at it, add the missing blank line after the function.

Note that Fractional Multiplication is not enabled by the driver,
but used only if the boot loaded enabled it before.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/1a58ebef6f54460f49fb81ba9bbf288164de2646.1721648548.git.geert+renesas@glider.be