arm: add support for Hisilicon HiSTB family SoCs

First supported chip is hi3798mv200 (which is similar to Hi3798cv200
used by poplar).

Signed-off-by: Yang Xiwen <forbidden405@outlook.com>
diff --git a/arch/arm/mach-histb/Makefile b/arch/arm/mach-histb/Makefile
new file mode 100644
index 0000000..7975c0f
--- /dev/null
+++ b/arch/arm/mach-histb/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier:	GPL-2.0+
+
+obj-y += sysmap-histb.o
+obj-y += board_common.o