ahci: add support for IBM Akebono platform device

commit 2435dcb9 upstream.

The new IBM Akebono board has a PPC476GTR SoC with an AHCI compliant
SATA controller. This patch adds a compatible property for the new SoC
to the AHCI platform driver.
Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Tejun Heo <tj@kernel.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/ata/ahci_platform.c

@@ -204,6 +204,7 @@ static int __devexit ahci_remove(struct platform_device *pdev)
 
 static const struct of_device_id ahci_of_match[] = {
 	{ .compatible = "calxeda,hb-ahci", },
+	{ .compatible = "ibm,476gtr-ahci", },
 	{},
 };
 MODULE_DEVICE_TABLE(of, ahci_of_match);