ARM: dts: microchip: sam9x75_curiosity: Add power monitor support

Add PAC1934 support in order to monitor the board power consumption.
Device is connected on flexcom7 in twi mode.

[root@SAM9X75 ~]$ awk -f pac1934.awk
VDD3V3 current:   10.675 mA, voltage: 3295.41 mV
VDDOUT4 current:  5.7625 mA, voltage: 1196.78 mV
VDDCORE current: 115.442 mA, voltage: 1243.65 mV
VDDIODDR current: 29.585 mA, voltage: 1345.21 mV

Signed-off-by: Mihai Sain <mihai.sain@microchip.com>
Link: https://lore.kernel.org/r/20241122080523.3941-3-mihai.sain@microchip.com
[claudiu.beznea: s/VDDOUT4/DCDC4 to comply with schematics]
Signed-off-by: Claudiu Beznea <claudiu.beznea@tuxon.dev>

Author: Mihai Sain

arch/arm/boot/dts/microchip/at91-sam9x75_curiosity.dts

@@ -198,6 +198,52 @@
 	};
 };
 
+&flx7 {
+	atmel,flexcom-mode = <ATMEL_FLEXCOM_MODE_TWI>;
+	status = "okay";
+};
+
+&i2c7 {
+	dmas = <0>, <0>;
+	i2c-analog-filter;
+	i2c-digital-filter;
+	i2c-digital-filter-width-ns = <35>;
+	pinctrl-names = "default";
+	pinctrl-0 = <&pinctrl_flx7_default>;
+	status = "okay";
+
+	power-monitor@10 {
+		compatible = "microchip,pac1934";
+		reg = <0x10>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		channel@1 {
+			reg = <0x1>;
+			shunt-resistor-micro-ohms = <10000>;
+			label = "VDD3V3";
+		};
+
+		channel@2 {
+			reg = <0x2>;
+			shunt-resistor-micro-ohms = <10000>;
+			label = "DCDC4";
+		};
+
+		channel@3 {
+			reg = <0x3>;
+			shunt-resistor-micro-ohms = <10000>;
+			label = "VDDCORE";
+		};
+
+		channel@4 {
+			reg = <0x4>;
+			shunt-resistor-micro-ohms = <10000>;
+			label = "VDDIODDR";
+		};
+	};
+};
+
 &i2s {
 	pinctrl-names = "default";
 	pinctrl-0 = <&pinctrl_i2s_default>;
@@ -231,6 +277,12 @@
 				<AT91_PIOA 24 AT91_PERIPH_A AT91_PINCTRL_PULL_UP>,
 				<AT91_PIOA 25 AT91_PERIPH_A AT91_PINCTRL_PULL_UP>;
 		};
+
+		pinctrl_flx7_default: flx7-default {
+			atmel,pins =
+				<AT91_PIOC 0 AT91_PERIPH_C AT91_PINCTRL_PULL_UP>,
+				<AT91_PIOC 1 AT91_PERIPH_C AT91_PINCTRL_PULL_UP>;
+		};
 	};
 
 	gpio-keys {