ARM: dts: stm32: add UserPA13 button on stm32mp135f-dk

The PA13 user button is connected to the PA13 pin of the stm32mp135f-dk
board. It requires an internal pull-up configuration.
Signed-off-by: Fabien Dessenne <fabien.dessenne@foss.st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>

arch/arm/boot/dts/stm32mp135f-dk.dts

@@ -7,6 +7,7 @@
 /dts-v1/;
 
 #include <dt-bindings/gpio/gpio.h>
+#include <dt-bindings/input/input.h>
 #include <dt-bindings/leds/common.h>
 #include "stm32mp135.dtsi"
 #include "stm32mp13xf.dtsi"
@@ -25,6 +26,16 @@ memory@c0000000 {
 		reg = <0xc0000000 0x20000000>;
 	};
 
+	gpio-keys {
+		compatible = "gpio-keys";
+
+		user-pa13 {
+			label = "User-PA13";
+			linux,code = <BTN_1>;
+			gpios = <&gpioa 13 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
+		};
+	};
+
 	leds {
 		compatible = "gpio-leds";