dt-bindings: clock: renesas,cpg-mssr: Document RZ/N2H support

dt-bindings: clock: renesas,cpg-mssr: Document RZ/N2H support

Document support for Module Standby and Software Reset found on the
Renesas RZ/N2H (R9A09G087) SoC.  The Module Standby and Software Reset
IP is similar to that found on the RZ/T2H SoC.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/20250609203656.333138-4-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>