clk: renesas: r8a779g0: Add SASYNCPER clocks

On R-Car V4H, all PLLs except PLL5 support Spread Spectrum and/or
Fractional Multiplication to reduce electromagnetic interference.

Add the SASYNCPER and SASYNCPERD[124] clocks, which are used as clock
sources for modules that must not be affected by Spread Spectrum and/or
Fractional Multiplication.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lore.kernel.org/r/d0f35c35e1f96c5a649ab477e7ba5d8025957cd0.1665147497.git.geert+renesas@glider.be