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/PCIPPC6.h b/include/configs/PCIPPC6.h
index 250b586..9202794 100644
--- a/include/configs/PCIPPC6.h
+++ b/include/configs/PCIPPC6.h
@@ -86,7 +86,7 @@
 #define CONFIG_PCI		1
 #define CONFIG_PCI_PNP		1	/* PCI plug-and-play */
 
-#define CFG_NAND_LEGACY
+#define CONFIG_NAND_LEGACY
 
 /*
  * Miscellaneous configurable options