ahci: add support for IBM Akebono platform device

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>
Cc: stable@vger.kernel.org
diff --git a/drivers/ata/ahci_platform.c b/drivers/ata/ahci_platform.c
index f955431..4b231ba 100644
--- a/drivers/ata/ahci_platform.c
+++ b/drivers/ata/ahci_platform.c
@@ -329,6 +329,7 @@
 static const struct of_device_id ahci_of_match[] = {
 	{ .compatible = "snps,spear-ahci", },
 	{ .compatible = "snps,exynos5440-ahci", },
+	{ .compatible = "ibm,476gtr-ahci", },
 	{},
 };
 MODULE_DEVICE_TABLE(of, ahci_of_match);