arm64: dts: renesas: r8a774a1: Use extended audio dmac registers

Basic audio dmac register only supports busif from 0 to 3,
in order to use busif4 ~ busif7 extended audio dmac registers
need to be used.

Based on similar work from Jiada Wang in commit 7a516e49 ("arm64:
dts: renesas: use extended audio dmac register").
Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

arch/arm64/boot/dts/renesas/r8a774a1.dtsi

@@ -1682,7 +1682,7 @@ rcar_sound: sound@ec500000 {
 				<0 0xec5a0000 0 0x100>,  /* ADG */
 				<0 0xec540000 0 0x1000>, /* SSIU */
 				<0 0xec541000 0 0x280>,  /* SSI */
-				<0 0xec740000 0 0x200>;  /* Audio DMAC peri peri*/
+				<0 0xec760000 0 0x200>;  /* Audio DMAC peri peri*/
 			reg-names = "scu", "adg", "ssiu", "ssi", "audmapp";
 
 			clocks = <&cpg CPG_MOD 1005>,