scripts/config_whitelist.txt: Fix after merging

CONFIG_SPIFLASH is manually re-added as it is not a new symbol, but now
only exists in CONFIG_SYS_EXTRA_OPTIONS.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/scripts/config_whitelist.txt b/scripts/config_whitelist.txt
index c98decb..36b8cc1 100644
--- a/scripts/config_whitelist.txt
+++ b/scripts/config_whitelist.txt
@@ -1226,6 +1226,7 @@
 CONFIG_SOFT_I2C_GPIO_SDA
 CONFIG_SOFT_I2C_READ_REPEATED_START
 CONFIG_SPD_EEPROM
+CONFIG_SPIFLASH
 CONFIG_SPI_ADDR
 CONFIG_SPI_BOOTING
 CONFIG_SPI_DATAFLASH_WRITE_VERIFY