configs: milkv_duo: Add spi nor configs

Add configs related to spi nor flash 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 1738796..0cb2922 100644
--- a/configs/milkv_duo_defconfig
+++ b/configs/milkv_duo_defconfig
@@ -37,3 +37,6 @@
 CONFIG_SYS_NS16550_MEM32=y
 CONFIG_SYSRESET=y
 CONFIG_SYSRESET_CV1800B=y
+CONFIG_SPI_FLASH_MACRONIX=y
+CONFIG_SPI=y
+CONFIG_CV1800B_SPIF=y