riscv: dts: sophgo: enable hardware clock (RTC) on the Milk-V Pioneer

These boards have a working hardware clock if you put a CR-1220
battery in them. We enable it using information from a 6.1.x vendor
kernel.

Reviewed-by: Chen Wang <unicorn_wang@outlook.com>
Signed-off-by: Michael Orlitzky <michael@orlitzky.com>
Link: https://lore.kernel.org/r/20260107112922.20013-2-michael@orlitzky.com
Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
Signed-off-by: Chen Wang <unicorn_wang@outlook.com>
Signed-off-by: Chen Wang <wangchen20@iscas.ac.cn>

Author: orlitzky

arch/riscv/boot/dts/sophgo/sg2042-milkv-pioneer.dts

@@ -52,6 +52,17 @@
 	status = "okay";
 };
 
+&i2c0 {
+	pinctrl-0 = <&i2c0_cfg>;
+	pinctrl-names = "default";
+	status = "okay";
+
+	rtc: rtc@68 {
+		compatible = "dallas,ds1307";
+		reg = <0x68>;
+	};
+};
+
 &i2c1 {
 	pinctrl-0 = <&i2c1_cfg>;
 	pinctrl-names = "default";
@@ -89,6 +100,16 @@
 		};
 	};
 
+	i2c0_cfg: i2c0-cfg {
+		i2c0-pins {
+			pinmux = <PINMUX(PIN_IIC0_SDA, 0)>,
+				 <PINMUX(PIN_IIC0_SCL, 0)>;
+			bias-pull-up;
+			drive-strength-microamp = <26800>;
+			input-schmitt-enable;
+		};
+	};
+
 	i2c1_cfg: i2c1-cfg {
 		i2c1-pins {
 			pinmux = <PINMUX(PIN_IIC1_SDA, 0)>,