dt-bindings: arm: renesas: Add HopeRun RZ/G2H boards

This patch adds board HiHope RZ/G2H (the main board, powered by the
R8A774E1) and board HiHope RZ/G2 EX (the expansion board that sits on top
of the HiHope RZ/G2H). Both boards are made by Jiangsu HopeRun Software
Co., Ltd. (a.k.a. HopeRun).

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/1594138692-16816-1-git-send-email-prabhakar.mahadev-lad.rj@bp.renesas.com


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