configs: sandbox64: Enable SF bootdev

Align the sandbox64 defconfig with sandbox defconfig. Enable missing
SPI NOT bootdev. This fixes ut_bootstd_bootdev_test_cmd_hunt test .

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/sandbox64_defconfig b/configs/sandbox64_defconfig
index 69e5efe..55a2b9a 100644
--- a/configs/sandbox64_defconfig
+++ b/configs/sandbox64_defconfig
@@ -165,6 +165,7 @@
 CONFIG_MMC_SANDBOX=y
 CONFIG_MTD=y
 CONFIG_SPI_FLASH_SANDBOX=y
+CONFIG_BOOTDEV_SPI_FLASH=y
 CONFIG_SPI_FLASH_ATMEL=y
 CONFIG_SPI_FLASH_EON=y
 CONFIG_SPI_FLASH_GIGADEVICE=y