mx35pdk: Allow booting of a device tree kernel

Select CONFIG_OF_LIBFDT, so that a dt kernel can be launched.
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>

include/configs/mx35pdk.h

@@ -95,6 +95,7 @@
 
 #include <config_cmd_default.h>
 
+#define CONFIG_OF_LIBFDT
 #define CONFIG_CMD_BOOTZ
 #define CONFIG_CMD_PING
 #define CONFIG_CMD_DHCP