arm64: dts: renesas: r8a774e1-hihope-rzg2h: Enable HS400 mode

This patch enables HS400 mode on HiHope RZ/G2H board.

Signed-off-by: Biju Das <biju.das@bp.renesas.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20200819080841.3475-1-biju.das.jz@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

arm64: dts: renesas: r8a774e1-hihope-rzg2h: Setup DU clocks

Setup up the required clocks for the DU to be functional.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://lore.kernel.org/r/20200812140217.24251-10-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

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>