drivers: ata: pata_arasan_cf: use the same name for the same lock

Note that `&acdev->host->lock' and `qc->ap->lock' denote the same lock, and it's
particularly confusing to spin_lock on the former but spin_unlock on the latter.

Signed-off-by: Iago Abal <mail@iagoabal.eu>
Signed-off-by: Tejun Heo <tj@kernel.org>

drivers/ata/pata_arasan_cf.c

@@ -565,7 +565,7 @@ chan_request_fail:
 	qc->ap->hsm_task_state = HSM_ST_ERR;
 
 	cf_ctrl_reset(acdev);
-	spin_unlock_irqrestore(qc->ap->lock, flags);
+	spin_unlock_irqrestore(&acdev->host->lock, flags);
 sff_intr:
 	dma_complete(acdev);
 }