dt-bindings: rtc: renesas,rz-rtca3: Add RZ/V2N support

dt-bindings: rtc: renesas,rz-rtca3: Add RZ/V2N support

The Renesas RZ/V2N (r9a09g056) RTC is identical to the RZ/V2H
(r9a09g057) variant. Add the compatible string for RZ/V2N and
extend the existing RZ/V2H reset configuration to cover both
variants.

Signed-off-by: Ovidiu Panait <ovidiu.panait.rb@renesas.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patch.msgid.link/20260125192706.27099-4-ovidiu.panait.rb@renesas.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>