dt-bindings: timer: renesas: ostm: Document Renesas RZ/V2H(P) SoC

Document the General Timer Module (a.k.a OSTM) block on Renesas RZ/V2H(P)
("R9A09G057") SoC, which is identical to the one found on the RZ/A1H and
RZ/G2L SoCs. Add the "renesas,r9a09g057-ostm" compatible string for the
RZ/V2H(P) SoC.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20240322151219.885832-2-prabhakar.mahadev-lad.rj@bp.renesas.com