arm64: dts: renesas: r9a09g087m44-rzn2h-evk: Add PHY interrupt support

arm64: dts: renesas: r9a09g087m44-rzn2h-evk: Add PHY interrupt support

Add interrupt support for the GMAC1 and GMAC2 PHYs on the RZ/N2H EVK
board. The PHYs are connected to the ICU via IRQ14 and IRQ15 lines
respectively.

Define RZN2H_IRQxx macros in the SoC DTSI to map the ICU IRQ_NS lines
to their absolute ICU interrupt space offsets.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patch.msgid.link/20260312160407.3387840-2-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>