PCI: xgene: Use inbound resources for setup

Now that the helpers provide the inbound resources in the host bridge
'dma_ranges' resource list, convert the Xgene host bridge to use the
resource list to setup the inbound addresses.

Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Andrew Murray <andrew.murray@arm.com>
Cc: Toan Le <toan@os.amperecomputing.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>