Document the Renesas RZ/G3S (R9A08G045) RIIC IP. This is compatible with
the version available on Renesas RZ/V2H (R9A09G075).
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>