headers: declare void arguments for functions

Not giving any argument means that any argument is OK,
this is not what is meant here.

Change-Id: Ide651c1dec973d4b8709cf00646988f4c4f3acdd

kernel/include/kmalloc.h

@@ -34,7 +34,7 @@ void *__kmalloc(int size, ihk_mc_ap_flag flag);
 void __kfree(void *ptr);
 
 int _memcheck(void *ptr, char *msg, char *file, int line, int free);
-int memcheckall();
+int memcheckall(void);
 int freecheck(int runcount);
 void kmalloc_consolidate_free_list(void);