mx35pdk: Allow booting of a device tree kernel

Select CONFIG_OF_LIBFDT, so that a dt kernel can be launched.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
diff --git a/include/configs/mx35pdk.h b/include/configs/mx35pdk.h
index 88b2bd6..0db92a7 100644
--- a/include/configs/mx35pdk.h
+++ b/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