mx28evk: Allow to booting a dt kernel

Allow to booting a dt kernel.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
diff --git a/include/configs/mx28evk.h b/include/configs/mx28evk.h
index 02f3366..cb4ff37 100644
--- a/include/configs/mx28evk.h
+++ b/include/configs/mx28evk.h
@@ -225,6 +225,7 @@
 #define CONFIG_BOOTCOMMAND	"run bootcmd_net"
 #define CONFIG_LOADADDR	0x42000000
 #define CONFIG_SYS_LOAD_ADDR	CONFIG_LOADADDR
+#define CONFIG_OF_LIBFDT
 
 /*
  * Extra Environments