ARM: dts: r8a7794: Use SYSC "always-on" PM Domain for sound

Hook up the Audio-DMAC and sound device nodes to the SYSC "always-on" PM
Domain, for a more consistent device-power-area description in DT.

Cfr. commit 0761ff2a ("ARM: dts: r8a7794: Add SYSC PM Domains").

Fixes: 320d6c5a ("ARM: dts: r8a7794: add sound support")
Fixes: 298e4ee3 ("ARM: dts: r8a7794: add Audio-DMAC support")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/r8a7794.dtsi

@@ -319,7 +319,7 @@ GIC_SPI 331 IRQ_TYPE_LEVEL_HIGH
 				  "ch12";
 		clocks = <&mstp5_clks R8A7794_CLK_AUDIO_DMAC0>;
 		clock-names = "fck";
-		power-domains = <&cpg_clocks>;
+		power-domains = <&sysc R8A7794_PD_ALWAYS_ON>;
 		#dma-cells = <1>;
 		dma-channels = <13>;
 	};
@@ -1485,7 +1485,7 @@ rcar_sound: sound@ec500000 {
 			      "mix.0", "mix.1",
 			      "dvc.0", "dvc.1",
 			      "clk_a", "clk_b", "clk_c", "clk_i";
-		power-domains = <&cpg_clocks>;
+		power-domains = <&sysc R8A7794_PD_ALWAYS_ON>;
 
 		status = "disabled";