arm64: dts: renesas: Add HiHope RZ/G2H main board support

Basic support for the HiHope RZ/G2H main board:
  - Memory,
  - Main crystal,
  - Serial console
  - eMMC

Signed-off-by: Marian-Cristian Rotariu <marian-cristian.rotariu.rb@bp.renesas.com>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/1594230511-24790-8-git-send-email-prabhakar.mahadev-lad.rj@bp.renesas.com


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