ramips: use SoC I2C instead of bitbanged for Ubiquiti ER-X-SFP

The original idea of bitbanged I2C is to use i2c-gpio-custom
Since i2c-gpio-custom is no longer available on 5.4, use SoC I2C instead

Signed-off-by: DENG Qingfang <dengqf6@mail2.sysu.edu.cn>

target/linux/ramips/dts/mt7621_ubiquiti_edgerouterx-sfp.dts

@@ -5,18 +5,13 @@
 / {
 	model = "UBNT-ERX-SFP";
 	compatible = "ubiquiti,edgerouterx-sfp", "mediatek,mt7621-soc";
+};
 
-	i2c-gpio {
-		compatible = "i2c-gpio";
-		gpios = <&gpio 3 GPIO_ACTIVE_HIGH /* sda */
-		         &gpio 4 GPIO_ACTIVE_HIGH /* scl */
-		        >;
-		#address-cells = <1>;
-		#size-cells = <0>;
+&i2c {
+	status = "okay";
 
-		pca9555@25 {
-			compatible = "pca9555";
-			reg = <0x25>;
-		};
+	pca9555@25 {
+		compatible = "nxp,pca9555";
+		reg = <0x25>;
 	};
 };

target/linux/ramips/dts/mt7621_ubiquiti_edgerouterx.dtsi

@@ -109,7 +109,7 @@
 
 &state_default {
 	gpio {
-		groups = "uart2", "uart3", "i2c", "pcie", "rgmii2", "jtag";
+		groups = "uart2", "uart3", "pcie", "rgmii2", "jtag";
 		function = "gpio";
 	};
 };

target/linux/ramips/image/mt7621.mk

@@ -785,7 +785,7 @@ define Device/ubiquiti_edgerouterx-sfp
   $(Device/ubiquiti_edgerouterx)
   DEVICE_VENDOR := Ubiquiti
   DEVICE_MODEL := EdgeRouter X-SFP
-  DEVICE_PACKAGES += kmod-i2c-algo-pca kmod-gpio-pca953x kmod-i2c-gpio-custom
+  DEVICE_PACKAGES += kmod-i2c-algo-pca kmod-gpio-pca953x
   SUPPORTED_DEVICES += ubnt-erx-sfp
 endef
 TARGET_DEVICES += ubiquiti_edgerouterx-sfp