PCI/ACPI: Check acpi_resource_to_address64() return value

We should check the acpi_resource_to_address64() return value, which
also removes the need to validate the resource type beforehand.
No functional change.

Found by Coverity (CID 113815).

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>