arm64: dts: renesas: Add initial device tree for RZ/V2N EVK

Add the initial device tree for the Renesas RZ/V2N EVK board, based on
the R9A09G056N48 SoC. Enable basic board functionality, including:
  - Memory mapping (reserve the first 128MB for the secure area)
  - Clock inputs (QEXTAL, RTXIN, AUDIO_EXTAL)
  - PINCTRL configurations for peripherals
  - Serial console (SCIF)
  - SDHI1 with power control and UHS modes

Update the Makefile to include the new DTB.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/20250407191628.323613-13-prabhakar.mahadev-lad.rj@bp.renesas.com


Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>