nvmet: exit debugfs after discovery subsystem exits

Commit 528589947c180 ("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 <[e-mail]>
Closes: https://lore.kernel.org/all/CAHj4cs96AfFQpyDKF_MdfJsnOEo=2V7dQgqjFv+k3t7H-=[e-mail]/
Fixes: 528589947c180 ("nvmet: initialize discovery subsys after debugfs is initialized")
Signed-off-by: Mohamed Khalfella <[e-mail]>
Reviewed-by: Hannes Reinecke <[e-mail]>
Reviewed-by: Daniel Wagner <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jens Axboe <[e-mail]>

drivers/nvme/target/core.c

···
 static void __exit nvmet_exit(void)
 {
 	nvmet_exit_configfs();
-	nvmet_exit_debugfs();
 	nvmet_exit_discovery();
+	nvmet_exit_debugfs();
 	ida_destroy(&cntlid_ida);
 	destroy_workqueue(nvmet_wq);
 	destroy_workqueue(buffered_io_wq);