fsnotify: remove unused declaration

fsnotify_alloc_event_holder() and fsnotify_destroy_event_holder()
has been removed since commit 7053aee2 ("fsnotify: do not share
events between notification groups"), so remove it.
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>

fs/notify/fsnotify.h

@@ -76,10 +76,6 @@ static inline void fsnotify_clear_marks_by_sb(struct super_block *sb)
  */
 extern void __fsnotify_update_child_dentry_flags(struct inode *inode);
 
-/* allocate and destroy and event holder to attach events to notification/access queues */
-extern struct fsnotify_event_holder *fsnotify_alloc_event_holder(void);
-extern void fsnotify_destroy_event_holder(struct fsnotify_event_holder *holder);
-
 extern struct kmem_cache *fsnotify_mark_connector_cachep;
 
 #endif	/* __FS_NOTIFY_FSNOTIFY_H_ */