ide: another possible ide panic fix for blk-end-request

I have reviewed all blk-end-request patches again to confirm whether
there are any similar problems with the last week's ide-cd panic:
    http://lkml.org/lkml/2008/1/29/140



And I found a possible similar bug in ide-io change:
ide_end_drive_cmd() could be called for blk_pc_request() which could
have bios.  To complete such requests correctly, we need to pass
the actual size of the request.
Otherwise, __blk_end_request() returns 1 because the request still has
bios, and the system will BUG() unnecessarily.

The following patch fixes the bug and should be applied on top of
Linus' git.

Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: Borislav Petkov <petkovbb@googlemail.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>