arm64: dts: rockchip: add support for rockpro64 board

PINE64 Rockpro 64 is a RK3399 development board, it
uses LPDDR4 memory.
http://wiki.pine64.org/index.php/ROCKPro64_Main_Page

CPU, GPU, memory, video codecs, audio codecs and HDMI
are verified and worked.

Change-Id: I6ac953eb6a8a217dc1049fe67752ed075c1a6485
Signed-off-by: ayaka <ayaka@soulik.info>
Signed-off-by: Randy Li <randy.li@rock-chips.com>

Author: hizukiayaka

arch/arm64/boot/dts/rockchip/Makefile

@@ -61,6 +61,7 @@ dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3399-gru-kevin-r0.dtb
 dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3399-gru-kevin-r1.dtb
 dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3399-mid-818-android-6.0.dtb
 dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3399-mid-818-android.dtb
+dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3399-rockpro64.dtb
 dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3399-rv1-android.dtb
 dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3399-sapphire-excavator-box-android-6.0.dtb
 dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3399-sapphire-excavator-box.dtb