ide: add ide_end_rq() (v2)
* Move request dequeuing from __ide_end_request() to ide_end_request().
* Rename __ide_end_request() to ide_end_rq() and export it.
* Fix ide_end_rq() to pass original blk_end_request() return value.
* ide_end_dequeued_request() is used only in cdrom_end_request()
so inline it there and then remove the function.
v2:
* Remove needless BUG_ON() while at it (start_request()'s one is enough).
There should be no functional changes caused by this patch.
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>