pata_arasan_cf: declare/use more local variables in arasan_cf_dma_start()

'acdev->qc', 'acdev->qc->ap', and 'acdev->qc->tf' expressions are used multiple
times in this function, so it makes sense to use the local variables for them.
Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/ata/pata_arasan_cf.c

@@ -674,13 +674,16 @@ void arasan_cf_error_handler(struct ata_port *ap)
 
 static void arasan_cf_dma_start(struct arasan_cf_dev *acdev)
 {
+	struct ata_queued_cmd *qc = acdev->qc;
+	struct ata_port *ap = qc->ap;
+	struct ata_taskfile *tf = &qc->tf;
 	u32 xfer_ctr = readl(acdev->vbase + XFER_CTR) & ~XFER_DIR_MASK;
-	u32 write = acdev->qc->tf.flags & ATA_TFLAG_WRITE;
+	u32 write = tf->flags & ATA_TFLAG_WRITE;
 
 	xfer_ctr |= write ? XFER_WRITE : XFER_READ;
 	writel(xfer_ctr, acdev->vbase + XFER_CTR);
 
-	acdev->qc->ap->ops->sff_exec_command(acdev->qc->ap, &acdev->qc->tf);
+	ap->ops->sff_exec_command(ap, tf);
 	ata_sff_queue_work(&acdev->work);
 }