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/at91rm9200dk.h b/include/configs/at91rm9200dk.h
index cd2eae2..fca431e 100644
--- a/include/configs/at91rm9200dk.h
+++ b/include/configs/at91rm9200dk.h
@@ -116,7 +116,7 @@
 #define CONFIG_CMD_MII
 #define CONFIG_CMD_NAND
 
-#define CFG_NAND_LEGACY
+#define CONFIG_NAND_LEGACY
 
 #define CFG_MAX_NAND_DEVICE	1	/* Max number of NAND devices		*/
 #define SECTORSIZE 512