fsnotify: switch send_to_group() and ->handle_event to const struct qstr *

note that conditions surrounding accesses to dname in audit_watch_handle_event()
and audit_mark_handle_event() guarantee that dname won't have been NULL.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

kernel/audit_tree.c

@@ -1040,7 +1040,7 @@ static void evict_chunk(struct audit_chunk *chunk)
 static int audit_tree_handle_event(struct fsnotify_group *group,
 				   struct inode *to_tell,
 				   u32 mask, const void *data, int data_type,
-				   const unsigned char *file_name, u32 cookie,
+				   const struct qstr *file_name, u32 cookie,
 				   struct fsnotify_iter_info *iter_info)
 {
 	return 0;