arm64: dts: renesas: r9a08g045: Add I3C node

arm64: dts: renesas: r9a08g045: Add I3C node

Add the I3C node to RZ/G3S SoC DTSI.

Signed-off-by: Quynh Nguyen <quynh.nguyen.xb@renesas.com>
[wsa: adapted to upstream driver, moved bus frequencies to board file]
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/20250807151434.5241-7-wsa+renesas@sang-engineering.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>