[PATCH] libata: fold __ata_qc_complete() into ata_qc_free()

All ata_qc_free() does is calling __ata_qc_complete() which isn't used
anywhere else.  Fold __ata_qc_complete() into ata_qc_free().

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>