dt-bindings: timer: renesas: ostm: Document RZ/Five SoC

The OSTM block on the RZ/Five SoC is identical to one found on the RZ/G2UL
SoC. "renesas,r9a07g043-ostm" compatible string will be used on the RZ/Five
SoC so to make this clear and to keep this file consistent, update the
comment to include RZ/Five SoC.

No driver changes are required as generic compatible string "renesas,ostm"
will be used as a fallback on RZ/Five 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/20231115212908.33131-1-prabhakar.mahadev-lad.rj@bp.renesas.com