arm: kirkwood: ib62x0: drop dev CONFIG_OF_LIBFDT

It is already defined in included mv-common.h file.

Signed-off-by: Luka Perkov <luka.perkov@sartura.hr>

include/configs/ib62x0.h

@@ -25,11 +25,6 @@
 /* Add target to build it automatically upon "make" */
 #define CONFIG_BUILD_TARGET     "u-boot.kwb"
 
-/*
- * Enable device tree support
- */
-#define CONFIG_OF_LIBFDT
-
 /*
  * Compression configuration
  */