ahci: added support for Freescale AHCI sata

Freescale introduced QorIQ series SOCs, like ls1021 ls2085, with AHCI
sata support. It complies with the serial ATA 3.0 specification
and the AHCI 1.3 specification.

Signed-off-by: Shaohui Xie <Shaohui.Xie@freescale.com>
Signed-off-by: Yuantian Tang <Yuantian.Tang@freescale.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Documentation/devicetree/bindings/ata/ahci-platform.txt

@@ -16,6 +16,8 @@ Required properties:
   - "snps,dwc-ahci"
   - "snps,exynos5440-ahci"
   - "snps,spear-ahci"
+  - "fsl,qoriq-ahci" : for qoriq series socs which include ls1021, ls2085, etc.
+  - "fsl,<chip>-ahci" : chip could be ls1021, ls2085 etc.
   - "generic-ahci"
 - interrupts        : <interrupt mapping for SATA IRQ>
 - reg               : <registers mapping>

drivers/ata/ahci_platform.c

@@ -74,6 +74,7 @@ static const struct of_device_id ahci_of_match[] = {
 	{ .compatible = "ibm,476gtr-ahci", },
 	{ .compatible = "snps,dwc-ahci", },
 	{ .compatible = "hisilicon,hisi-ahci", },
+	{ .compatible = "fsl,qoriq-ahci", },
 	{},
 };
 MODULE_DEVICE_TABLE(of, ahci_of_match);