MX5: Enable flat-device-tree support on mx51/53 evk board

device tree for uboot arm support has already been enabled
in the master branch. This patch enable device tree support
for mx51/53 evk board for DT test.

Signed-off-by: Jason Liu <r64343@freescale.com>

include/configs/mx51evk.h

@@ -224,4 +224,7 @@
 #define CONFIG_ENV_IS_IN_MMC
 #define CONFIG_SYS_MMC_ENV_DEV 0
 
+#define CONFIG_OF_LIBFDT
+#define CONFIG_SYS_BOOTMAPSZ   0x800000
+
 #endif

include/configs/mx53evk.h

@@ -190,4 +190,7 @@
 #define CONFIG_ENV_IS_IN_MMC
 #define CONFIG_SYS_MMC_ENV_DEV 0
 
+#define CONFIG_OF_LIBFDT
+#define CONFIG_SYS_BOOTMAPSZ   0x800000
+
 #endif				/* __CONFIG_H */