ARM: dts: r8a7778: Use R-Car Gen1 Ether fallback compat string

Use newly added R-Car Gen1 Ether fallback compat string
in the DT of the r8a7778 SoC.

This should have no run-time effect as the driver matches against
the per-SoC compat string before considering the fallback compat string.

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

arch/arm/boot/dts/r8a7778.dtsi

@@ -51,7 +51,8 @@
 	};
 
 	ether: ethernet@fde00000 {
-		compatible = "renesas,ether-r8a7778";
+		compatible = "renesas,ether-r8a7778",
+			     "renesas,rcar-gen1-ether";
 		reg = <0xfde00000 0x400>;
 		interrupts = <GIC_SPI 105 IRQ_TYPE_LEVEL_HIGH>;
 		clocks = <&mstp1_clks R8A7778_CLK_ETHER>;