ARM: dts: r8a7742-iwg21d-q7: Add iWave G21D-Q7 board based on RZ/G1H

Add support for iWave RainboW-G21D-Qseven board based on RZ/G1H.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Marian-Cristian Rotariu <marian-cristian.rotariu.rb@bp.renesas.com>
Link: https://lore.kernel.org/r/1588542414-14826-11-git-send-email-prabhakar.mahadev-lad.rj@bp.renesas.com


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