PCI: layerscape: Add support for LS1043a and LS2080a

Both LS1043a and LS2080a are based on ARMv8 64-bit architecture and have
similar PCIe implementation.  LUT is added to controller.

Add LS1043a and LS2080a support.

[bhelgaas: move unused field removal into separate patch, include DT update]
Signed-off-by: Bhupesh Sharma <bhupesh.sharma@freescale.com> (DT update)
Signed-off-by: Minghuan Lian <Minghuan.Lian@freescale.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Arnd Bergmann <arnd@arndb.de> (DT update)

Documentation/devicetree/bindings/pci/layerscape-pci.txt

@@ -1,10 +1,20 @@
 Freescale Layerscape PCIe controller
 
-This PCIe host controller is based on the Synopsis Designware PCIe IP
+This PCIe host controller is based on the Synopsys DesignWare PCIe IP
 and thus inherits all the common properties defined in designware-pcie.txt.
 
+This controller derives its clocks from the Reset Configuration Word (RCW)
+which is used to describe the PLL settings at the time of chip-reset.
+
+Also as per the available Reference Manuals, there is no specific 'version'
+register available in the Freescale PCIe controller register set,
+which can allow determining the underlying DesignWare PCIe controller version
+information.
+
 Required properties:
-- compatible: should contain the platform identifier such as "fsl,ls1021a-pcie"
+- compatible: should contain the platform identifier such as:
+        "fsl,ls1021a-pcie", "snps,dw-pcie"
+        "fsl,ls2080a-pcie", "snps,dw-pcie"
 - reg: base addresses and lengths of the PCIe controller
 - interrupts: A list of interrupt outputs of the controller. Must contain an
   entry for each entry in the interrupt-names property.