ARM: dts: at91: sama5d27_som1_ek: set USER button as a wakeup source

Set the USER button as a wakeup source to allow wakeup from ULP0.
Signed-off-by: Ludovic Desroches <ludovic.desroches@microchip.com>
[claudiu.beznea@microchip.com: change subject to match the desired prefix]
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

arch/arm/boot/dts/at91-sama5d27_som1_ek.dts

@@ -516,6 +516,7 @@ pb4 {
 			label = "USER";
 			gpios = <&pioA PIN_PA29 GPIO_ACTIVE_LOW>;
 			linux,code = <0x104>;
+			wakeup-source;
 		};
 	};