arm64: dts: imx8mp-tqma8mpql-mba8mpxl: Enable wakeup-source for GPIO buttons

These buttons are capable of waking up a suspended system, add the
appropriate property for both.
Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mp-tqma8mpql-mba8mpxl.dts

@@ -80,12 +80,14 @@ switch-1 {
 			label = "S12";
 			linux,code = <BTN_0>;
 			gpios = <&gpio5 27 GPIO_ACTIVE_LOW>;
+			wakeup-source;
 		};
 
 		switch-2 {
 			label = "S13";
 			linux,code = <BTN_1>;
 			gpios = <&gpio5 26 GPIO_ACTIVE_LOW>;
+			wakeup-source;
 		};
 	};