arm: dts: rockchip: Add dts for rk3308 evb

Add dts for rk3308 evb, sync from the linux kernel
upstream list [0].

[0]https://patchwork.kernel.org/patch/11201555/

Signed-off-by: Andy Yan <andy.yan@rock-chips.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/arch/arm/dts/rk3308-u-boot.dtsi b/arch/arm/dts/rk3308-u-boot.dtsi
new file mode 100644
index 0000000..1a68dec
--- /dev/null
+++ b/arch/arm/dts/rk3308-u-boot.dtsi
@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ *(C) Copyright 2019 Rockchip Electronics Co., Ltd
+ */
+
+&cru {
+	u-boot,dm-pre-reloc;
+};
+
+&dmc {
+	u-boot,dm-pre-reloc;
+};
+
+&emmc {
+	u-boot,dm-pre-reloc;
+};
+
+&grf {
+	u-boot,dm-pre-reloc;
+};
+
+&saradc {
+	u-boot,dm-pre-reloc;
+	status = "okay";
+};