Don't enable memory or I/O decoding if we haven't assigned or claimed the
BAR's resource.
If we enable decoding for a BAR that hasn't been assigned an address, we'll
likely cause bus conflicts. This declines to enable decoding for resources
with IORESOURCE_UNSET.
Note that drivers can use pci_enable_device_io() or pci_enable_device_mem()
if they only care about specific types of BARs. In that case, we don't
bother checking whether the corresponding resources are assigned or
claimed.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
3cedcc3621