PCI: Clean up resource allocation in devm_of_pci_get_host_bridge_resources()

Instead of first allocating and then freeing memory for struct resource in
case we cannot parse a PCI resource from the device tree, work against a
local struct and kmemdup() it when we decide to go with it.

Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>