ARM: shmobile: r8a7791 dtsi: Add CPG/MSTP Clock Domain for sound

797a0626 ("ARM: shmobile: r8a7791 dtsi: Add CPG/MSTP Clock Domain")
added CPG/MSTP clock-cells domain support, but it was missing sound
support. This patch adds it.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
[horms: updated commit id referred to in changelog]
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/r8a7791.dtsi

@@ -1677,6 +1677,7 @@ rcar_sound: sound@ec500000 {
 				"mix.0", "mix.1",
 				"dvc.0", "dvc.1",
 				"clk_a", "clk_b", "clk_c", "clk_i";
+		power-domains = <&cpg_clocks>;
 
 		status = "disabled";