pata: imx: support controller modes up to PIO4

Having timing settings for all supported by the controller PIO modes
now it is possible to expand its PIO mask.

Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/drivers/ata/pata_imx.c b/drivers/ata/pata_imx.c
index 8f13c9f..d4caa23 100644
--- a/drivers/ata/pata_imx.c
+++ b/drivers/ata/pata_imx.c
@@ -160,7 +160,7 @@
 	ap = host->ports[0];
 
 	ap->ops = &pata_imx_port_ops;
-	ap->pio_mask = ATA_PIO0;
+	ap->pio_mask = ATA_PIO4;
 	ap->flags |= ATA_FLAG_SLAVE_POSS;
 
 	io_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);