ts4800: add CONFIG_OF_LIBFDT

Linux only boots IMX.51-based boards with device tree, so this board
would benefit from supporting it.

Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
Cc: Stefano Babic <sbabic@denx.de>
diff --git a/include/configs/ts4800.h b/include/configs/ts4800.h
index fbca8a6..2f6c97c 100644
--- a/include/configs/ts4800.h
+++ b/include/configs/ts4800.h
@@ -24,6 +24,8 @@
 
 #define CONFIG_HW_WATCHDOG
 
+#define CONFIG_OF_LIBFDT
+
 #define CONFIG_MACH_TYPE	MACH_TYPE_TS48XX
 
 /* text base address used when linking */