dt-bindings: power: axp20x-usb: add axp223 compatible

This adds the "x-powers,axp223-usb-power-supply" to the list of
compatibles for AXP20X VBUS power supply driver.
Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

Documentation/devicetree/bindings/power/supply/axp20x_usb_power.txt

@@ -3,6 +3,11 @@ AXP20x USB power supply
 Required Properties:
 -compatible: One of: "x-powers,axp202-usb-power-supply"
                      "x-powers,axp221-usb-power-supply"
+                     "x-powers,axp223-usb-power-supply"
+
+The AXP223 PMIC shares most of its behaviour with the AXP221 but has slight
+variations such as the former being able to set the VBUS power supply max
+current to 100mA, unlike the latter.
 
 This node is a subnode of the axp20x PMIC.