rockchip: rk3308: Add dts for ROC-RK3308-CC

Add dts file for ROC-RK3308-CC from firefly.

Sync form linux rockchip for v5.5-armsoc/dts64:
"arm64: dts: rockchip: Add devicetree for board roc-rk3308-cc"
(sha1: 4403e1237be3af0977aa23ef399e3496316317a0)

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-roc-cc-u-boot.dtsi b/arch/arm/dts/rk3308-roc-cc-u-boot.dtsi
new file mode 100644
index 0000000..ffbe742
--- /dev/null
+++ b/arch/arm/dts/rk3308-roc-cc-u-boot.dtsi
@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2018-2019 Rockchip Electronics Co., Ltd
+ */
+#include "rk3308-u-boot.dtsi"
+
+/ {
+	chosen {
+		u-boot,spl-boot-order = "same-as-spl", &emmc;
+	};
+};
+
+&uart2 {
+	u-boot,dm-pre-reloc;
+	clock-frequency = <24000000>;
+	status = "okay";
+};