ARM: dts: stm32: Add push button to stm32f769 Discovery board

Add node for user push button.
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>

arch/arm/boot/dts/stm32f769-disco.dts

@@ -73,6 +73,18 @@ red {
 			gpios = <&gpioj 13 GPIO_ACTIVE_HIGH>;
 		};
 	};
+
+	gpio_keys {
+		compatible = "gpio-keys";
+		#address-cells = <1>;
+		#size-cells = <0>;
+		autorepeat;
+		button@0 {
+			label = "User";
+			linux,code = <KEY_HOME>;
+			gpios = <&gpioa 0 GPIO_ACTIVE_HIGH>;
+		};
+	};
 };
 
 &cec {