arm64: dts: allwinner: h6: Add RX DMA channel for SPDIF

The SPDIF hardware found on the H6 supports both transmit and receive
functions. However it is missing the RX DMA channel.

Add the SPDIF hardware block's RX DMA channel. Also remove the
by-default pinmux, since the end device can choose to implement
either or both functionalities.

Fixes: f95b598d ("arm64: dts: allwinner: Add SPDIF node for Allwinner H6")
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Link: https://lore.kernel.org/r/20240127163247.384439-6-wens@kernel.org


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