ARM: dts: r8a7791: use fallback can compatibility string

Use recently added fallback compatibility string in r8a7791 device tree.
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>

arch/arm/boot/dts/r8a7791.dtsi

@@ -1013,7 +1013,7 @@ du_out_lvds0: endpoint {
 	};
 
 	can0: can@e6e80000 {
-		compatible = "renesas,can-r8a7791";
+		compatible = "renesas,can-r8a7791", "renesas,rcar-gen2-can";
 		reg = <0 0xe6e80000 0 0x1000>;
 		interrupts = <GIC_SPI 186 IRQ_TYPE_LEVEL_HIGH>;
 		clocks = <&mstp9_clks R8A7791_CLK_RCAN0>,
@@ -1024,7 +1024,7 @@ can0: can@e6e80000 {
 	};
 
 	can1: can@e6e88000 {
-		compatible = "renesas,can-r8a7791";
+		compatible = "renesas,can-r8a7791", "renesas,rcar-gen2-can";
 		reg = <0 0xe6e88000 0 0x1000>;
 		interrupts = <GIC_SPI 187 IRQ_TYPE_LEVEL_HIGH>;
 		clocks = <&mstp9_clks R8A7791_CLK_RCAN1>,