PCI: designware: 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: changelog]
Tested-by: James Morse <james.morse@arm.com>
Tested-by: Gabriel Fernandez <gabriel.fernandez@st.com>
Tested-by: Minghuan Lian <Minghuan.Lian@freescale.com>
Signed-off-by: Zhou Wang <wangzhou1@hisilicon.com>
Signed-off-by: Gabriele Paoloni <gabriele.paoloni@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Pratyush Anand <pratyush.anand@gmail.com>