arm64: dts: allwinner: a64: Remove unused SPDIF sound card

As of v5.7-rc2, Linux now prints the following message at boot:

  [   33.848525] platform sound_spdif: deferred probe pending

This is because sound_spdif is waiting on its CPU DAI &spdif to probe,
but &spdif is disabled in the device tree.

Exposure of the SPDIF pin is board-specific functionality, so the sound
card and codec DAI belong in the individual board DTS, not the SoC DTSI.
In fact, no in-tree A64 board DTS enables &spdif, so let's remove the
card and DAI entirely.

This reverts commit 78e07137.
Acked-by: Clément Péron <peron.clem@gmail.com>
Signed-off-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>

arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi

@@ -154,24 +154,6 @@ link_codec: simple-audio-card,codec {
 		};
 	};
 
-	sound_spdif {
-		compatible = "simple-audio-card";
-		simple-audio-card,name = "On-board SPDIF";
-
-		simple-audio-card,cpu {
-			sound-dai = <&spdif>;
-		};
-
-		simple-audio-card,codec {
-			sound-dai = <&spdif_out>;
-		};
-	};
-
-	spdif_out: spdif-out {
-		#sound-dai-cells = <0>;
-		compatible = "linux,spdif-dit";
-	};
-
 	timer {
 		compatible = "arm,armv8-timer";
 		allwinner,erratum-unknown1;