configs: airoha: an7581_evb: Enable Airoha SNFI SPI config

Enable Airoha SNFI SPI config to enable support for SNAND flash.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
diff --git a/configs/an7581_evb_defconfig b/configs/an7581_evb_defconfig
index fa41a4b..c74247e 100644
--- a/configs/an7581_evb_defconfig
+++ b/configs/an7581_evb_defconfig
@@ -78,3 +78,4 @@
 CONFIG_SHA512=y
 CONFIG_AIROHA_ETH=y
 CONFIG_MMC_MTK=y
+CONFIG_AIROHA_SNFI_SPI=y