ARM: dts: bcm23550: Add SoC-specific I2C compatible

Add BCM23550-specific compatible for brcm,kona-i2c nodes. While not
currently used by the i2c-bcm-kona driver, they can serve for further
customization, if required.
Done in preparation for dt-binding coversion to DT schema.
Signed-off-by: Stanislav Jakubek <stano.jakubek@gmail.com>
Link: https://lore.kernel.org/r/9875ec0211187e4f5e2a4379c63eacdb69b31d7a.1682252615.git.stano.jakubek@gmail.comSigned-off-by: Florian Fainelli <f.fainelli@gmail.com>

arch/arm/boot/dts/bcm23550.dtsi

@@ -159,7 +159,7 @@ uartb3: serial@2000 {
 		};
 
 		bsc1: i2c@16000 {
-			compatible = "brcm,kona-i2c";
+			compatible = "brcm,bcm23550-i2c", "brcm,kona-i2c";
 			reg = <0x00016000 0x70>;
 			interrupts = <GIC_SPI 103 IRQ_TYPE_LEVEL_HIGH>;
 			#address-cells = <1>;
@@ -169,7 +169,7 @@ bsc1: i2c@16000 {
 		};
 
 		bsc2: i2c@17000 {
-			compatible = "brcm,kona-i2c";
+			compatible = "brcm,bcm23550-i2c", "brcm,kona-i2c";
 			reg = <0x00017000 0x70>;
 			interrupts = <GIC_SPI 102 IRQ_TYPE_LEVEL_HIGH>;
 			#address-cells = <1>;
@@ -179,7 +179,7 @@ bsc2: i2c@17000 {
 		};
 
 		bsc3: i2c@18000 {
-			compatible = "brcm,kona-i2c";
+			compatible = "brcm,bcm23550-i2c", "brcm,kona-i2c";
 			reg = <0x00018000 0x70>;
 			interrupts = <GIC_SPI 169 IRQ_TYPE_LEVEL_HIGH>;
 			#address-cells = <1>;
@@ -189,7 +189,7 @@ bsc3: i2c@18000 {
 		};
 
 		bsc4: i2c@1c000 {
-			compatible = "brcm,kona-i2c";
+			compatible = "brcm,bcm23550-i2c", "brcm,kona-i2c";
 			reg = <0x0001c000 0x70>;
 			interrupts = <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>;
 			#address-cells = <1>;