dts: add support for Rockchip rk3399 soc

These files are from kernel upstream:
"649a371 Add linux-next specific files for 20160616"
with some modification need by U-Boot:
- chosen with stdout-path to uart2.
- add clock-frequency for uart2

Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/dts/Makefile b/arch/arm/dts/Makefile
index 88741e5..c97e3f6 100644
--- a/arch/arm/dts/Makefile
+++ b/arch/arm/dts/Makefile
@@ -32,7 +32,8 @@
 	rk3288-jerry.dtb \
 	rk3288-rock2-square.dtb \
 	rk3288-evb.dtb \
-	rk3036-sdk.dtb
+	rk3036-sdk.dtb \
+	rk3399-evb.dtb
 dtb-$(CONFIG_ARCH_MESON) += \
 	meson-gxbb-odroidc2.dtb
 dtb-$(CONFIG_TEGRA) += tegra20-harmony.dtb \