ARM: shmobile: r8a779x: use SoC-specific usb-dmac compatibility strings

Use recently SoC-specific compatibility strings in r8a779[01] device trees.
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/r8a7790.dtsi

@@ -386,7 +386,7 @@ audma1: dma-controller@ec720000 {
 	};
 
 	usb_dmac0: dma-controller@e65a0000 {
-		compatible = "renesas,usb-dmac";
+		compatible = "renesas,r8a7790-usb-dmac", "renesas,usb-dmac";
 		reg = <0 0xe65a0000 0 0x100>;
 		interrupts = <0 109 IRQ_TYPE_LEVEL_HIGH
 			      0 109 IRQ_TYPE_LEVEL_HIGH>;
@@ -398,7 +398,7 @@ usb_dmac0: dma-controller@e65a0000 {
 	};
 
 	usb_dmac1: dma-controller@e65b0000 {
-		compatible = "renesas,usb-dmac";
+		compatible = "renesas,r8a7790-usb-dmac", "renesas,usb-dmac";
 		reg = <0 0xe65b0000 0 0x100>;
 		interrupts = <0 110 IRQ_TYPE_LEVEL_HIGH
 			      0 110 IRQ_TYPE_LEVEL_HIGH>;

arch/arm/boot/dts/r8a7791.dtsi

@@ -375,7 +375,7 @@ audma1: dma-controller@ec720000 {
 	};
 
 	usb_dmac0: dma-controller@e65a0000 {
-		compatible = "renesas,usb-dmac";
+		compatible = "renesas,r8a7791-usb-dmac", "renesas,usb-dmac";
 		reg = <0 0xe65a0000 0 0x100>;
 		interrupts = <0 109 IRQ_TYPE_LEVEL_HIGH
 			      0 109 IRQ_TYPE_LEVEL_HIGH>;
@@ -387,7 +387,7 @@ usb_dmac0: dma-controller@e65a0000 {
 	};
 
 	usb_dmac1: dma-controller@e65b0000 {
-		compatible = "renesas,usb-dmac";
+		compatible = "renesas,r8a7791-usb-dmac", "renesas,usb-dmac";
 		reg = <0 0xe65b0000 0 0x100>;
 		interrupts = <0 110 IRQ_TYPE_LEVEL_HIGH
 			      0 110 IRQ_TYPE_LEVEL_HIGH>;