rockchip: rk3399: Add Ficus EE board support

Add board support for Ficus EE board from Vamrs. This board utilizes
common Rock960 family support.

Following peripherals are tested and known to work:
* Gigabit Ethernet
* USB 2.0
* MMC

Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
[Reworked based on common Rock960 family support]
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
diff --git a/arch/arm/dts/Makefile b/arch/arm/dts/Makefile
index dc319bc..949ee47 100644
--- a/arch/arm/dts/Makefile
+++ b/arch/arm/dts/Makefile
@@ -42,6 +42,7 @@
 	rk3288-veyron-minnie.dtb \
 	rk3288-vyasa.dtb \
 	rk3328-evb.dtb \
+	rk3399-ficus.dtb \
 	rk3368-lion.dtb \
 	rk3368-sheep.dtb \
 	rk3368-geekbox.dtb \