PCI: xilinx: Use of_pci_get_host_bridge_resources() to parse DT

Use the new of_pci_get_host_bridge_resources() API in place of the PCI OF
DT parser.

[bhelgaas: revise changelog to show similarity to 0021d22b ("PCI: designware: Use of_pci_get_host_bridge_resources() to parse DT")]
Signed-off-by: Bharat Kumar Gogada <bharatku@xilinx.com>
Signed-off-by: Ravi Kiran Gummaluri <rgummal@xilinx.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Michal Simek <michal.simek@xilinx.com>