drivers/mtd/nand: Move conditional compilation to Makefile

rename CFG_NAND_LEGACY to CONFIG_NAND_LEGACY

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
diff --git a/include/configs/IDS8247.h b/include/configs/IDS8247.h
index 29dc623..029bb99 100644
--- a/include/configs/IDS8247.h
+++ b/include/configs/IDS8247.h
@@ -262,7 +262,7 @@
  */
 #if defined(CONFIG_CMD_NAND)
 
-#define CFG_NAND_LEGACY
+#define CONFIG_NAND_LEGACY
 #define CFG_NAND0_BASE 0xE1000000
 
 #define CFG_MAX_NAND_DEVICE     1       /* Max number of NAND devices           */