riscv: board: Add nx25-ae250 to support RISC-V

Add nx25-ae250 board to do platform initializations.

Signed-off-by: Rick Chen <rick@andestech.com>
Signed-off-by: Rick Chen <rickchen36@gmail.com>
Signed-off-by: Greentime Hu <green.hu@gmail.com>
diff --git a/board/AndesTech/nx25-ae250/Makefile b/board/AndesTech/nx25-ae250/Makefile
new file mode 100644
index 0000000..66b6814
--- /dev/null
+++ b/board/AndesTech/nx25-ae250/Makefile
@@ -0,0 +1,8 @@
+#
+# Copyright (C) 2017 Andes Technology Corporation.
+# Rick Chen, Andes Technology Corporation <rick@andestech.com>
+#
+# SPDX-License-Identifier:	GPL-2.0+
+#
+
+obj-y	:= nx25-ae250.o