ARM: dts: mmp3-dell-ariel: Add the embedded controller

Add the device node for the computer's embedded controller, responsible
for controlling the LEDs and system power.
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Link: https://lore.kernel.org/r/20210121034130.1381872-10-lkundrak@v3.sk'
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/arm/boot/dts/mmp3-dell-ariel.dts

@@ -95,6 +95,15 @@ &twsi3 {
 
 &twsi4 {
 	status = "okay";
+
+	embedded-controller@58 {
+		compatible = "dell,wyse-ariel-ec", "ene,kb3930";
+		reg = <0x58>;
+		system-power-controller;
+
+		off-gpios = <&gpio 126 GPIO_ACTIVE_HIGH>,
+			    <&gpio 127 GPIO_ACTIVE_HIGH>;
+	};
 };
 
 &ssp1 {