arm64: dts: renesas: r8a774e1: Add audio support

Add sound support for the RZ/G2H SoC (a.k.a. R8A774E1).
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/1594919915-5225-16-git-send-email-prabhakar.mahadev-lad.rj@bp.renesas.comSigned-off-by: Geert Uytterhoeven <geert+renesas@glider.be>