arm: at91: dt: sam9263ek: use rts/cts pinctrl group for uart0

Acked-by: NNicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NJean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

arch/arm/boot/dts/at91sam9263ek.dts

@@ -38,6 +38,7 @@
 			};
 
 			usart0: serial@fff8c000 {
+				pinctrl-0 = <&pinctrl_uart0 &pinctrl_uart0_rts_cts>;
 				status = "okay";
 			};