configs: milkv_duo: Add sysreset configs

Add sysreset configs as well as poweroff and reset commands for Sophgo
Milk-V Duo board.

Signed-off-by: Kongyang Liu <seashell11234455@gmail.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
diff --git a/configs/milkv_duo_defconfig b/configs/milkv_duo_defconfig
index e8413d7..28bd4b5 100644
--- a/configs/milkv_duo_defconfig
+++ b/configs/milkv_duo_defconfig
@@ -19,6 +19,7 @@
 CONFIG_SYS_PROMPT="milkv_duo# "
 CONFIG_CMD_MMC=y
 CONFIG_CMD_PART=y
+CONFIG_CMD_POWEROFF=y
 CONFIG_CMD_FAT=y
 CONFIG_CMD_FS_GENERIC=y
 CONFIG_ENV_OVERWRITE=y
@@ -30,3 +31,5 @@
 CONFIG_MMC_SDHCI_CV1800B=y
 CONFIG_SYS_NS16550=y
 CONFIG_SYS_NS16550_MEM32=y
+CONFIG_SYSRESET=y
+CONFIG_SYSRESET_CV1800B=y