drivers/mtd: Move conditional compilation to Makefile

rename CFG_FLASH_CFI_DRIVER to CONFIG_FLASH_CFI_DRIVER

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
diff --git a/include/configs/DU440.h b/include/configs/DU440.h
index 64c9ac0..c757523 100644
--- a/include/configs/DU440.h
+++ b/include/configs/DU440.h
@@ -119,7 +119,7 @@
  * FLASH related
  */
 #define CFG_FLASH_CFI			/* The flash is CFI compatible */
-#define CFG_FLASH_CFI_DRIVER		/* Use common CFI driver       */
+#define CONFIG_FLASH_CFI_DRIVER		/* Use common CFI driver       */
 
 #define CFG_FLASH_BANKS_LIST	{ CFG_FLASH_BASE }