ARM: dts: rockchip: fixes the bt on rk3036 kylin board

This patch fixes the BT power reported the failure message.
As following:
root@linaro-alip:~# echo 1 > /sys/class/rfkill/rfkill0/state
[  892.558269] rockchip-pinctrl pinctrl: pin gpio0-19 already requested
by 20060000.serial; cannot claim for wireless-bluetooth
[  892.571052] rockchip-pinctrl pinctrl: pin-19 (wireless-bluetooth) status -22
...

And for now, the BT can work with this patch.
root@linaro-alip:~# echo 1 > /sys/class/rfkill/rfkill0/state
[   69.328768] [BT_RFKILL]: ENABLE UART_RTS
[   69.438540] [BT_RFKILL]: DISABLE UART_RTS
[   69.443117] [BT_RFKILL]: bt turn on power
...

root@linaro-alip:~# hcitool dev
Devices:
        hci0    94:A1:A2:E9:2D:18

And
root@linaro-alip:~# bluetoothctl
[NEW] Controller 94:A1:A2:E9:2D:18 linaro-alip [default]
[bluetooth]# scan on
Discovery started
[CHG] Controller 94:A1:A2:E9:2D:18 Discovering: yes
..

Change-Id: I2148f4203300ab4265fd3ba718f0d3ec0c57e7ca
Signed-off-by: Caesar Wang <wxt@rock-chips.com>

arch/arm/boot/dts/rk3036-kylin.dts

@@ -388,6 +388,7 @@
 };
 
 &uart0 {
+	pinctrl-0 = <&uart0_xfer>, <&uart0_cts>;
 	status = "okay";
 };