Init: Remove unused variables

For build-system CFLAGS clean-up, fix unused variables.

Use a #define instead of static variable in a header file.

Change-Id: Id47bf38e51644b61a9f3ac1893a16553695f1aac
diff --git a/init/util.h b/init/util.h
index 04b8129..4cfe99d 100644
--- a/init/util.h
+++ b/init/util.h
@@ -22,7 +22,7 @@
 
 #define ARRAY_SIZE(x) (sizeof(x)/sizeof(x[0]))
 
-static const char *coldboot_done = "/dev/.coldboot_done";
+#define COLDBOOT_DONE "/dev/.coldboot_done"
 
 int mtd_name_to_number(const char *name);
 int create_socket(const char *name, int type, mode_t perm,