arm64: dts: allwinner: h616: Add SPDIF device node

The H616 SoC has an SPDIF transmitter hardware block, which has the same
layout as the one in the H6, minus the receiver side.

Add a device node for it, and a default pinmux.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Link: https://lore.kernel.org/r/20240127163247.384439-8-wens@kernel.org


Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>