arm64: dts: allwinner: Enable button wakeup on Orange Pi PC2

The Orange Pi PC2 features a GPIO button. As the button is connected to
Port L (pin PL3), it can be used as a wakeup source. Enable this.
Signed-off-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>

arch/arm64/boot/dts/allwinner/sun50i-h5-orangepi-pc2.dts

@@ -61,6 +61,7 @@ sw4 {
 			label = "sw4";
 			linux,code = <BTN_0>;
 			gpios = <&r_pio 0 3 GPIO_ACTIVE_LOW>;
+			wakeup-source;
 		};
 	};