ata: ahci_platform: Add synopsys ahci controller in DT's compatible list

SPEAr13xx series of SoCs contain Synopsys AHCI SATA Controller which shares
ahci_platform driver with other controller versions.

This patch updates DT compatible list for ahci_platform. It also updates and
renames binding documentation to more generic name.

Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Cc: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/ata/ahci_platform.c

@@ -280,6 +280,7 @@ static struct dev_pm_ops ahci_pm_ops = {
 
 static const struct of_device_id ahci_of_match[] = {
 	{ .compatible = "calxeda,hb-ahci", },
+	{ .compatible = "snps,spear-ahci", },
 	{},
 };
 MODULE_DEVICE_TABLE(of, ahci_of_match);