G clock is sourced from PLL3 and PLL6. The output of the mux is
connected to divider.

This patch adds a mux and divider for getting different rates from
this clock sources.
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20211203115154.31864-3-biju.das.jz@bp.renesas.comSigned-off-by: Geert Uytterhoeven <geert+renesas@glider.be>