ARM: shmobile: r8a7791 dtsi: Use generic names for device nodes

rcar_sound -> sound
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/r8a7791.dtsi

@@ -1494,7 +1494,7 @@ ipmmu_gp: mmu@e62a0000 {
 		status = "disabled";
 	};
 
-	rcar_sound: rcar_sound@ec500000 {
+	rcar_sound: sound@ec500000 {
 		/*
 		 * #sound-dai-cells is required
 		 *