fanotify: support secondary dir fh and name in fanotify_info

Allow storing a secondary dir fh and name tupple in fanotify_info.
This will be used to store the new parent and name information in
FAN_RENAME event.

Link: https://lore.kernel.org/r/20211129201537.1932819-8-amir73il@gmail.com


Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>