arm64: dts: r8a7795: Add SoC-specific compatible property to audio-dmac nodes

The audio-dmac nodes used the generic compatible property only.
Add the SoC-specific one, to make it future proof.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

arch/arm64/boot/dts/renesas/r8a7795.dtsi

@@ -328,7 +328,8 @@
 		};
 
 		audma0: dma-controller@ec700000 {
-			compatible = "renesas,rcar-dmac";
+			compatible = "renesas,dmac-r8a7795",
+				     "renesas,rcar-dmac";
 			reg = <0 0xec700000 0 0x10000>;
 			interrupts = <GIC_SPI 350 IRQ_TYPE_LEVEL_HIGH
 				      GIC_SPI 320 IRQ_TYPE_LEVEL_HIGH
@@ -360,7 +361,8 @@
 		};
 
 		audma1: dma-controller@ec720000 {
-			compatible = "renesas,rcar-dmac";
+			compatible = "renesas,dmac-r8a7795",
+				     "renesas,rcar-dmac";
 			reg = <0 0xec720000 0 0x10000>;
 			interrupts = <GIC_SPI 351 IRQ_TYPE_LEVEL_HIGH
 				      GIC_SPI 336 IRQ_TYPE_LEVEL_HIGH