scsi: osd: initiator should use mq variant of request ending

This is currently wrong since it isn't dependent on if we're using mq or
not. At least now it'll be correct when we force mq.

Cc: linux-scsi@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>