arm: kirkwood: ib62x0: drop CONFIG_MACH_TYPE

Mainline kernel for this device has only support for device tree. We can safely
drop this legacy code.

Signed-off-by: Luka Perkov <luka.perkov@sartura.hr>
diff --git a/include/configs/ib62x0.h b/include/configs/ib62x0.h
index 594fceb..9f1dc8a 100644
--- a/include/configs/ib62x0.h
+++ b/include/configs/ib62x0.h
@@ -23,11 +23,6 @@
 #define CONFIG_SKIP_LOWLEVEL_INIT	/* disable board lowlevel_init */
 
 /*
- * Machine type
- */
-#define CONFIG_MACH_TYPE	MACH_TYPE_NAS6210
-
-/*
  * Enable device tree support
  */
 #define CONFIG_OF_LIBFDT