spi: Remove CONFIG_OF_SPI_FLASH

Previous patches removed the last usages of this config variable, so
that it is now obsolete.

This patch removes it from the whitelist.

Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Jagan Teki <jagan@openedev.com>
Signed-off-by: Mario Six <mario.six@gdsys.cc>
diff --git a/scripts/config_whitelist.txt b/scripts/config_whitelist.txt
index 6704745..b3e0b71 100644
--- a/scripts/config_whitelist.txt
+++ b/scripts/config_whitelist.txt
@@ -1554,7 +1554,6 @@
 CONFIG_ODROID_REV_AIN
 CONFIG_OFF_PADCONF
 CONFIG_OF_
-CONFIG_OF_SPI_FLASH
 CONFIG_OF_STDOUT_PATH
 CONFIG_OMAP_EHCI_PHY1_RESET_GPIO
 CONFIG_OMAP_EHCI_PHY2_RESET_GPIO