clk: renesas: rzv2h: Add support for static mux clocks

clk: renesas: rzv2h: Add support for static mux clocks

Add support for `CLK_TYPE_SMUX` to register static muxed clocks on the
Renesas RZ/V2H(P) SoC.  Extend `cpg_core_clk` to include parent names,
mux flags, and a new `smuxed` struct.  Update clock registration to
handle static mux clocks.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/20250407165202.197570-2-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>