dt-bindings: i2c: renesas,riic: Document RZ/T2H and RZ/N2H support

dt-bindings: i2c: renesas,riic: Document RZ/T2H and RZ/N2H support

Document support for the I2C Bus Interface (RIIC) found on the Renesas
RZ/T2H (R9A09G077) and RZ/N2H (R9A09G087) SoCs.

The RIIC IP on these parts is similar to that on RZ/V2H(P) but supports
only four interrupts (including a combined error/event), lacks FM+ mode,
and does not require reset. Introduce a new compatible string
`renesas,riic-r9a09g077` for RZ/T2H and use it as a fallback for RZ/N2H.

Unlike earlier SoCs that use eight distinct interrupts, the RZ/T2H uses
only four. Update the binding schema to reflect this interrupt layout
and skip the `resets` property check, as it is not required on these SoCs.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20250625104526.101004-3-prabhakar.mahadev-lad.rj@bp.renesas.com