ARM: dts: imx6ul-kontron-n6x1x: Add 'chosen' node with 'stdout-path'

The Kontron N6x1x SoMs all use uart4 as a debug serial interface.
Therefore we set it in the 'chosen' node.

Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
(cherry picked from commit 36f42bb4d7f90cea20bfb56dd7ab2aa8d0929ca7)
Signed-off-by: Andrey Zhizhikin <andrey.zhizhikin@leica-geosystems.com>

arch/arm/boot/dts/imx6ul-kontron-n6x1x-som-common.dtsi

@@ -7,6 +7,12 @@
 
 #include <dt-bindings/gpio/gpio.h>
 
+/ {
+	chosen {
+		stdout-path = &uart4;
+	};
+};
+
 &ecspi2 {
 	cs-gpios = <&gpio4 22 GPIO_ACTIVE_HIGH>;
 	pinctrl-names = "default";