rockchip: rk3188: add -u-boot.dtsi for rock-rk3188

We should a -u-boot.dtsi for those config need by U-Boot only,
and other part sync with kernel.

Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
Acked-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
diff --git a/arch/arm/dts/rk3188-radxarock-u-boot.dtsi b/arch/arm/dts/rk3188-radxarock-u-boot.dtsi
new file mode 100644
index 0000000..5d650b1
--- /dev/null
+++ b/arch/arm/dts/rk3188-radxarock-u-boot.dtsi
@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) 2018 Fuzhou Rockchip Electronics Co., Ltd.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+&cru {
+	u-boot,dm-spl;
+};
+
+&pinctrl {
+	u-boot,dm-spl;
+};
+
+&uart2 {
+	status = "okay";
+	u-boot,dm-spl;
+};