libata: remove reading alt_status from ata_hsm_qc_complete()

In ata_hsm_qc_complete():
Calling ata_altstatus() after the qc is completed might race with next qc. Remove it.
Signed-off-by: Albert Lee <albertcc@tw.ibm.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/ata/libata-core.c

@@ -4781,8 +4781,6 @@ static void ata_hsm_qc_complete(struct ata_queued_cmd *qc, int in_wq)
 		} else
 			ata_qc_complete(qc);
 	}
-
-	ata_altstatus(ap); /* flush */
 }
 
 /**