ARM: dts: imx6ul-kontron-bl-common: Fix RTS polarity for RS485 interface

The polarity of the DE signal of the transceiver is active-high for
sending. Therefore rs485-rts-active-low is wrong and needs to be
removed to make RS485 transmissions work.

Signed-off-by: Annette Kobou <annette.kobou@kontron.de>
Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Fixes: 1ea4b76 ("ARM: dts: imx6ul-kontron-n6310: Add Kontron i.MX6UL N6310 SoM and boards")
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

Author: Annette Kobou

arch/arm/boot/dts/nxp/imx/imx6ul-kontron-bl-common.dtsi

@@ -168,7 +168,6 @@
 	pinctrl-0 = <&pinctrl_uart2>;
 	linux,rs485-enabled-at-boot-time;
 	rs485-rx-during-tx;
-	rs485-rts-active-low;
 	uart-has-rtscts;
 	status = "okay";
 };