dt-bindings: PCI: altera: Add altr,pcie-root-port-2.0

Add support for altr,pcie-root-port-2.0.
Signed-off-by: Ley Foon Tan <ley.foon.tan@intel.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/pci/altera-pcie.txt

 * Altera PCIe controller
 
 Required properties:
-- compatible :	should contain "altr,pcie-root-port-1.0"
+- compatible :	should contain "altr,pcie-root-port-1.0" or "altr,pcie-root-port-2.0"
 - reg:		a list of physical base address and length for TXS and CRA.
+		For "altr,pcie-root-port-2.0", additional HIP base address and length.
 - reg-names:	must include the following entries:
 		"Txs": TX slave port region
 		"Cra": Control register access region
+		"Hip": Hard IP region (if "altr,pcie-root-port-2.0")
 - interrupts:	specifies the interrupt source of the parent interrupt
 		controller.  The format of the interrupt specifier depends
 		on the parent interrupt controller.