HID: autosuspend -- fix lockup of hid on reset

This fixes a use of flush_scheduled_work() in USB HID's reset logic that can
deadlock.

Tested-by: Valdis Kletniks <Valdis.Kletnieks@vt.edu>
Signed-off-by: Oliver Neukum <oliver@neukum.name>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>