treewide: Switch DEFINE_TIMER callbacks to struct timer_list *

This changes all DEFINE_TIMER() callbacks to use a struct timer_list
pointer instead of unsigned long. Since the data argument has already been
removed, none of these callbacks are using their argument currently, so
this renames the argument to "unused".

Done using the following semantic patch:

@match_define_timer@
declarer name DEFINE_TIMER;
identifier _timer, _callback;
@@

 DEFINE_TIMER(_timer, _callback);

@change_callback depends on match_define_timer@
identifier match_define_timer._callback;
type _origtype;
identifier _origarg;
@@

 void
-_callback(_origtype _origarg)
+_callback(struct timer_list *unused)
 { ... }

Signed-off-by: Kees Cook <keescook@chromium.org>

security/keys/gc.c

@@ -29,7 +29,7 @@ DECLARE_WORK(key_gc_work, key_garbage_collector);
 /*
  * Reaper for links from keyrings to dead keys.
  */
-static void key_gc_timer_func(unsigned long);
+static void key_gc_timer_func(struct timer_list *);
 static DEFINE_TIMER(key_gc_timer, key_gc_timer_func);
 
 static time_t key_gc_next_run = LONG_MAX;
@@ -84,7 +84,7 @@ void key_schedule_gc_links(void)
  * Some key's cleanup time was met after it expired, so we need to get the
  * reaper to go through a cycle finding expired keys.
  */
-static void key_gc_timer_func(unsigned long data)
+static void key_gc_timer_func(struct timer_list *unused)
 {
 	kenter("");
 	key_gc_next_run = LONG_MAX;