block/laptop_mode: Convert timers to use timer_setup()

In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to using the new timer_setup() and from_timer()
to pass the timer pointer explicitly.

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Jeff Layton <jlayton@redhat.com>
Cc: linux-block@vger.kernel.org
Cc: linux-mm@kvack.org
Signed-off-by: Kees Cook <keescook@chromium.org>

include/linux/writeback.h

@@ -308,7 +308,7 @@ static inline void cgroup_writeback_umount(void)
 void laptop_io_completion(struct backing_dev_info *info);
 void laptop_sync_completion(void);
 void laptop_mode_sync(struct work_struct *work);
-void laptop_mode_timer_fn(unsigned long data);
+void laptop_mode_timer_fn(struct timer_list *t);
 #else
 static inline void laptop_sync_completion(void) { }
 #endif