arm64: dts: rockchip: enable spdif on Quartz64 A

Add the necessary nodes to enable the spdif output on the
RK3566-Quartz-A board.

Co-developed-by: Peter Geis <pgwipeout@gmail.com>
Signed-off-by: Peter Geis <pgwipeout@gmail.com>
Signed-off-by: Nicolas Frattaroli <frattaroli.nicolas@gmail.com>
Link: https://lore.kernel.org/r/20211015111303.1365328-2-frattaroli.nicolas@gmail.com


Signed-off-by: Heiko Stuebner <heiko@sntech.de>