nds32: Support AE3XX platform.

Support Andestech AE3xx platform: serial, timer device tree flow.

Signed-off-by: rick <rick@andestech.com>
diff --git a/arch/nds32/Kconfig b/arch/nds32/Kconfig
index 4fcd01d..d72ff46 100644
--- a/arch/nds32/Kconfig
+++ b/arch/nds32/Kconfig
@@ -11,8 +11,12 @@
 config TARGET_ADP_AG101P
 	bool "Support adp-ag101p"
 
+config TARGET_ADP_AE3XX
+	bool "Support adp-ae3xx"
+
 endchoice
 
 source "board/AndesTech/adp-ag101p/Kconfig"
+source "board/AndesTech/adp-ae3xx/Kconfig"
 
 endmenu