fsnotify: tidy up FS_ and FAN_ constants

Order by value, so the free value ranges are easier to find.

Link: https://lore.kernel.org/r/20200319151022.31456-2-amir73il@gmail.com


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