M28: Enable FDT support

This will eventually be needed with Linux 3.5, which will be the point when
MXS will be switched to FDT.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Detlev Zundel <dzu@denx.de>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <festevam@gmail.com>

include/configs/m28evk.h

@@ -43,6 +43,8 @@
 #define	CONFIG_ARCH_CPU_INIT
 #define	CONFIG_ARCH_MISC_INIT
 
+#define CONFIG_OF_LIBFDT
+
 /*
  * SPL
  */