ARM: dtsi: axp81x: add USB power supply node

The AXP813/818 has a VBUS power input. Add a device node for it, now
that we support it.
Signed-off-by: Quentin Schulz <quentin.schulz@bootlin.com>
[wens@csie.org: Add commit message]
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>

arch/arm/boot/dts/axp81x.dtsi

@@ -171,4 +171,8 @@ reg_drivevbus: drivevbus {
 			status = "disabled";
 		};
 	};
+
+	usb_power_supply: usb-power-supply {
+		compatible = "x-powers,axp813-usb-power-supply";
+	};
 };