ata: pci: enable bus mastering

The non DM code path already would enable pci bus mastering. Do the
same for the DM code path.

Fixes AHCI problems I am seeing on an Intel Apollolake device.

Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
[trini: Use ahci_dev not dev in the calls]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 6998b82..cb2c648 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1152,7 +1152,12 @@
 int ahci_probe_scsi_pci(struct udevice *ahci_dev)
 {
 	ulong base;
-	u16 vendor, device;
+	u16 vendor, device, cmd;
+
+	/* Enable bus mastering */
+	dm_pci_read_config16(ahci_dev, PCI_COMMAND, &cmd);
+	cmd |= PCI_COMMAND_MASTER;
+	dm_pci_write_config16(ahci_dev, PCI_COMMAND, cmd);
 
 	base = (ulong)dm_pci_map_bar(ahci_dev, PCI_BASE_ADDRESS_5, 0, 0,
 				     PCI_REGION_TYPE, PCI_REGION_MEM);