nds32: Support AE3XX platform.

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

Signed-off-by: rick <rick@andestech.com>
diff --git a/configs/adp-ag101p_defconfig b/configs/adp-ag101p_defconfig
index 685a961..afcfa18 100644
--- a/configs/adp-ag101p_defconfig
+++ b/configs/adp-ag101p_defconfig
@@ -6,6 +6,7 @@
 CONFIG_SYS_PROMPT="NDS32 # "
 CONFIG_CMD_MMC=y
 # CONFIG_CMD_SETEXPR is not set
+CONFIG_CMD_DHCP=y
 CONFIG_CMD_PING=y
 CONFIG_CMD_CACHE=y
 CONFIG_CMD_DATE=y