arm64: dts: renesas: rzg2l-smarc: Add WM8978 sound codec

Add WM8978 sound codec node to RZ/G2L SMARC EVK.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20210921084605.16250-3-biju.das.jz@bp.renesas.com


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