Move macro constant into the only file, which uses it.

ir/be/bechordal_t.h

@@ -38,9 +38,6 @@
 #include "beirg.h"
 #include "beifg.h"
 
-/** Defines an invalid register index. */
-#define NO_COLOR (-1)
-
 /**
  * A liveness interval border.
  */

ir/be/becopyheur.c

@@ -47,6 +47,9 @@
 
 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
 
+/** Defines an invalid register index. */
+#define NO_COLOR (-1)
+
 #define SEARCH_FREE_COLORS
 
 #define SLOTS_PINNED_GLOBAL 64