ARM: dts: imx6-tx6: enable support for rtscts on UARTs

Add missing pinctrl for the RTS/CTS lines to uart1 and set the
fsl,uart-has-rtscts property on all UARTs to enable support for HW
handshake.
Signed-off-by: Lothar Waßmann <LW@KARO-electronics.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/imx6qdl-tx6.dtsi

@@ -688,19 +688,22 @@ &ssi1 {
 
 &uart1 {
 	pinctrl-names = "default";
-	pinctrl-0 = <&pinctrl_uart1>;
+	pinctrl-0 = <&pinctrl_uart1 &pinctrl_uart1_rtscts>;
+	fsl,uart-has-rtscts;
 	status = "okay";
 };
 
 &uart2 {
 	pinctrl-names = "default";
 	pinctrl-0 = <&pinctrl_uart2 &pinctrl_uart2_rtscts>;
+	fsl,uart-has-rtscts;
 	status = "okay";
 };
 
 &uart3 {
 	pinctrl-names = "default";
 	pinctrl-0 = <&pinctrl_uart3 &pinctrl_uart3_rtscts>;
+	fsl,uart-has-rtscts;
 	status = "okay";
 };