ide: use __ide_end_request() in ide_end_dequeued_request()

* Remove dead code for handling IDE TCQ from ide_end_dequeued_request().

* Add 'dequeue' parameter to __ide_end_request().

* Use __ide_end_request() in ide_end_dequeued_request().

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>