arm64: dts: renesas: r8a77961: Enable Sound / Audio-DMAC

This patch enables Sound and Audio-DMAC for R-Car M3-W+ (R8A77961).
It is tested on R-Car M3-W+ Salvator-XS board.
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87h7sovdvt.wl-kuninori.morimoto.gx@renesas.comSigned-off-by: Geert Uytterhoeven <geert+renesas@glider.be>