irqchip/renesas-rzv2h: Add support for RZ/V2N SoC

irqchip/renesas-rzv2h: Add support for RZ/V2N SoC

Add support for the RZ/V2N Interrupt Control Unit (ICU) by introducing a
dedicated compatible string in the irqchip driver. While the RZ/V2N ICU
differs from the RZ/V2H(P) version in its register layout primarily due
to a reduced set of ECCRAM related registers the irqchip driver does not
currently access these registers.

As a result, the RZ/V2N ICU can be safely handled by rzv2h_icu_probe for
now, but it still requires a distinct compatible so that future changes
can differentiate the SoCs when needed.

[ tglx: Fixed up the made up subject prefix ]

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://patch.msgid.link/20251127162447.320971-3-prabhakar.mahadev-lad.rj@bp.renesas.com