sata_via: apply magic FIFO fix to vt6420 too

vt6420 has the same FIFO overflow problem as vt6421 when combined with
certain devices.  This patch applies the magic fix to vt6420 too.
Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-by: NMartin Qvist <q@maq.dk>
Reported-by: NPeter Zijlstra <peterz@infradead.org>
Cc: Joseph Chan <JosephChan@via.com.tw>
Cc: stable@kernel.org
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

drivers/ata/sata_via.c

@@ -538,7 +538,7 @@ static int vt8251_prepare_host(struct pci_dev *pdev, struct ata_host **r_host)
 	return 0;
 }
 
-static void svia_configure(struct pci_dev *pdev)
+static void svia_configure(struct pci_dev *pdev, int board_id)
 {
 	u8 tmp8;
 
@@ -577,7 +577,7 @@ static void svia_configure(struct pci_dev *pdev)
 	}
 
 	/*
-	 * vt6421 has problems talking to some drives.  The following
+	 * vt6420/1 has problems talking to some drives.  The following
 	 * is the fix from Joseph Chan <JosephChan@via.com.tw>.
 	 *
 	 * When host issues HOLD, device may send up to 20DW of data
@@ -596,8 +596,9 @@ static void svia_configure(struct pci_dev *pdev)
 	 *
 	 * https://bugzilla.kernel.org/show_bug.cgi?id=15173
 	 * http://article.gmane.org/gmane.linux.ide/46352
+	 * http://thread.gmane.org/gmane.linux.kernel/1062139
 	 */
-	if (pdev->device == 0x3249) {
+	if (board_id == vt6420 || board_id == vt6421) {
 		pci_read_config_byte(pdev, 0x52, &tmp8);
 		tmp8 |= 1 << 2;
 		pci_write_config_byte(pdev, 0x52, tmp8);
@@ -652,7 +653,7 @@ static int svia_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 	if (rc)
 		return rc;
 
-	svia_configure(pdev);
+	svia_configure(pdev, board_id);
 
 	pci_set_master(pdev);
 	return ata_host_activate(host, pdev->irq, ata_bmdma_interrupt,