ARM: dts: r8a7778: Use R-Car Gen 1 fallback binding for i2c nodes

Use recently added R-Car Gen 1 fallback binding for i2c nodes in
DT for r8a7778 SoC.

This has no run-time effect for the current driver as the initialisation
sequence is the same for the SoC-specific binding for r8a7778 and the
fallback binding for R-Car Gen 1.
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

arch/arm/boot/dts/r8a7778.dtsi

@@ -150,7 +150,7 @@ pfc: pfc@fffc0000 {
 	i2c0: i2c@ffc70000 {
 		#address-cells = <1>;
 		#size-cells = <0>;
-		compatible = "renesas,i2c-r8a7778";
+		compatible = "renesas,i2c-r8a7778", "renesas,rcar-gen1-i2c";
 		reg = <0xffc70000 0x1000>;
 		interrupts = <GIC_SPI 67 IRQ_TYPE_LEVEL_HIGH>;
 		clocks = <&mstp0_clks R8A7778_CLK_I2C0>;
@@ -161,7 +161,7 @@ i2c0: i2c@ffc70000 {
 	i2c1: i2c@ffc71000 {
 		#address-cells = <1>;
 		#size-cells = <0>;
-		compatible = "renesas,i2c-r8a7778";
+		compatible = "renesas,i2c-r8a7778", "renesas,rcar-gen1-i2c";
 		reg = <0xffc71000 0x1000>;
 		interrupts = <GIC_SPI 78 IRQ_TYPE_LEVEL_HIGH>;
 		clocks = <&mstp0_clks R8A7778_CLK_I2C1>;
@@ -172,7 +172,7 @@ i2c1: i2c@ffc71000 {
 	i2c2: i2c@ffc72000 {
 		#address-cells = <1>;
 		#size-cells = <0>;
-		compatible = "renesas,i2c-r8a7778";
+		compatible = "renesas,i2c-r8a7778", "renesas,rcar-gen1-i2c";
 		reg = <0xffc72000 0x1000>;
 		interrupts = <GIC_SPI 76 IRQ_TYPE_LEVEL_HIGH>;
 		clocks = <&mstp0_clks R8A7778_CLK_I2C2>;
@@ -183,7 +183,7 @@ i2c2: i2c@ffc72000 {
 	i2c3: i2c@ffc73000 {
 		#address-cells = <1>;
 		#size-cells = <0>;
-		compatible = "renesas,i2c-r8a7778";
+		compatible = "renesas,i2c-r8a7778", "renesas,rcar-gen1-i2c";
 		reg = <0xffc73000 0x1000>;
 		interrupts = <GIC_SPI 77 IRQ_TYPE_LEVEL_HIGH>;
 		clocks = <&mstp0_clks R8A7778_CLK_I2C3>;