ARM: dt: axp209: Add AXP209 GPIO driver

Add the AXP209 GPIO node to our AXP209 DTSI so that boards can use it.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>

arch/arm/boot/dts/axp209.dtsi

@@ -53,6 +53,12 @@ &axp209 {
 	interrupt-controller;
 	#interrupt-cells = <1>;
 
+	axp_gpio: gpio {
+		compatible = "x-powers,axp209-gpio";
+		gpio-controller;
+		#gpio-cells = <2>;
+	};
+
 	regulators {
 		/* Default work frequency for buck regulators */
 		x-powers,dcdc-freq = <1500>;