ARM: rockchip: rk3188: enable pull-ups on UART RX pins

The default behaviour of the uart-rx pins on the rk3188 is to be pulled up and
a lot of designs use diodes to even prevent them from being raised from the
outside.

Therefore change the rx-pin settings accordingly.

This also fixes a uart receive problem on mass production Radxa Rock boards.
Signed-off-by: Max Schwarz <max.schwarz@online.de>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

arch/arm/boot/dts/rk3188.dtsi

@@ -149,7 +149,7 @@ pcfg_pull_none: pcfg_pull_none {
 
 			uart0 {
 				uart0_xfer: uart0-xfer {
-					rockchip,pins = <RK_GPIO1 0 RK_FUNC_1 &pcfg_pull_none>,
+					rockchip,pins = <RK_GPIO1 0 RK_FUNC_1 &pcfg_pull_up>,
 							<RK_GPIO1 1 RK_FUNC_1 &pcfg_pull_none>;
 				};
 
@@ -164,7 +164,7 @@ uart0_rts: uart0-rts {
 
 			uart1 {
 				uart1_xfer: uart1-xfer {
-					rockchip,pins = <RK_GPIO1 4 RK_FUNC_1 &pcfg_pull_none>,
+					rockchip,pins = <RK_GPIO1 4 RK_FUNC_1 &pcfg_pull_up>,
 							<RK_GPIO1 5 RK_FUNC_1 &pcfg_pull_none>;
 				};
 
@@ -179,7 +179,7 @@ uart1_rts: uart1-rts {
 
 			uart2 {
 				uart2_xfer: uart2-xfer {
-					rockchip,pins = <RK_GPIO1 8 RK_FUNC_1 &pcfg_pull_none>,
+					rockchip,pins = <RK_GPIO1 8 RK_FUNC_1 &pcfg_pull_up>,
 							<RK_GPIO1 9 RK_FUNC_1 &pcfg_pull_none>;
 				};
 				/* no rts / cts for uart2 */
@@ -187,7 +187,7 @@ uart2_xfer: uart2-xfer {
 
 			uart3 {
 				uart3_xfer: uart3-xfer {
-					rockchip,pins = <RK_GPIO1 10 RK_FUNC_1 &pcfg_pull_none>,
+					rockchip,pins = <RK_GPIO1 10 RK_FUNC_1 &pcfg_pull_up>,
 							<RK_GPIO1 11 RK_FUNC_1 &pcfg_pull_none>;
 				};