arm64: dts: renesas: white-hawk: Add R-Car Sound support

Add R-Car Sound support for the White Hawk board with the
ARD-AUDIO-DA7212 external audio board, using a DT overlay.

Signed-off-by: Linh Phung <linh.phung.jy@renesas.com>
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/87o7p5l9t7.wl-kuninori.morimoto.gx@renesas.com


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