nvmet: exit debugfs after discovery subsystem exits

Commit 52858994 ("nvmet: initialize discovery subsys after debugfs
is initialized") changed nvmet_init() to initialize nvme discovery after
"nvmet" debugfs directory is initialized. The change broke nvmet_exit()
because discovery subsystem now depends on debugfs. Debugfs should be
destroyed after discovery subsystem. Fix nvmet_exit() to do that.

Reported-by: Yi Zhang <yi.zhang@redhat.com>
Closes: https://lore.kernel.org/all/CAHj4cs96AfFQpyDKF_MdfJsnOEo=2V7dQgqjFv+k3t7H-=yGhA@mail.gmail.com/


Fixes: 52858994 ("nvmet: initialize discovery subsys after debugfs is initialized")
Signed-off-by: Mohamed Khalfella <mkhalfella@purestorage.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Daniel Wagner <dwagner@suse.de>
Link: https://lore.kernel.org/r/20250807053507.2794335-1-mkhalfella@purestorage.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>