ARM64: poplar: hi3798cv200: u-boot support for Poplar 96Boards

This port adds support for:
        1) Serial
        2) eMMC
        3) USB

It has been tested with ARM TRUSTED FIRMWARE running u-boot as the
BL33 executable [see board's README]

eMMC has been tested for reading and booting the loader and linux
kernels as well as saving the u-boot environment.

USB has been tested with ASIX networking adapter and SanDisk 7.4GB
drive.

PSCI has been tested via the reset call (PSCI executes from DDR)

The firwmare upgrade process has been tested via TFTP and USB FAT
filesystem containing the fastboot.bin image in one of the partitions.

Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 3c3f5f7..5f2048b 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -837,6 +837,19 @@
 	  Support for HiKey 96boards platform. It features a HI6220
 	  SoC, with 8xA53 CPU, mali450 gpu, and 1GB RAM.
 
+config TARGET_POPLAR
+	bool "Support Poplar 96boards Enterprise Edition Platform"
+	select ARM64
+	select DM
+	select OF_CONTROL
+	select DM_SERIAL
+	select DM_USB
+	  help
+	  Support for Poplar 96boards EE platform. It features a HI3798cv200
+	  SoC, with 4xA53 CPU, 1GB RAM and the high performance Mali T720 GPU
+	  making it capable of running any commercial set-top solution based on
+	  Linux or Android.
+
 config TARGET_LS1012AQDS
 	bool "Support ls1012aqds"
 	select ARCH_LS1012A
@@ -1165,6 +1178,7 @@
 source "board/gumstix/pepper/Kconfig"
 source "board/h2200/Kconfig"
 source "board/hisilicon/hikey/Kconfig"
+source "board/hisilicon/poplar/Kconfig"
 source "board/imx31_phycore/Kconfig"
 source "board/isee/igep003x/Kconfig"
 source "board/olimex/mx23_olinuxino/Kconfig"