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/cpu/arm920t/s3c24x0/nand.c b/cpu/arm920t/s3c24x0/nand.c
index e1bf128..14882cb 100644
--- a/cpu/arm920t/s3c24x0/nand.c
+++ b/cpu/arm920t/s3c24x0/nand.c
@@ -27,7 +27,7 @@
 #endif
 
 #if defined(CONFIG_CMD_NAND)
-#if !defined(CFG_NAND_LEGACY)
+#if !defined(CONFIG_NAND_LEGACY)
 
 #include <nand.h>
 #include <s3c2410.h>
diff --git a/cpu/arm926ejs/davinci/nand.c b/cpu/arm926ejs/davinci/nand.c
index 8fd784e..2aa01d6 100644
--- a/cpu/arm926ejs/davinci/nand.c
+++ b/cpu/arm926ejs/davinci/nand.c
@@ -45,7 +45,7 @@
 #include <asm/io.h>
 
 #ifdef CFG_USE_NAND
-#if !defined(CFG_NAND_LEGACY)
+#if !defined(CONFIG_NAND_LEGACY)
 
 #include <nand.h>
 #include <asm/arch/nand_defs.h>
diff --git a/cpu/ppc4xx/ndfc.c b/cpu/ppc4xx/ndfc.c
index 4f083d9..72acfd0 100644
--- a/cpu/ppc4xx/ndfc.c
+++ b/cpu/ppc4xx/ndfc.c
@@ -31,7 +31,7 @@
 
 #include <common.h>
 
-#if defined(CONFIG_CMD_NAND) && !defined(CFG_NAND_LEGACY) && \
+#if defined(CONFIG_CMD_NAND) && !defined(CONFIG_NAND_LEGACY) && \
 	(defined(CONFIG_440EP) || defined(CONFIG_440GR) ||	     \
 	 defined(CONFIG_440EPX) || defined(CONFIG_440GRX) ||	     \
 	 defined(CONFIG_405EZ) || defined(CONFIG_405EX) ||	     \