PCI: Remove unnecessary initializations

We always assign "fields" immediately, so remove the unnecessary
initializations.  No functional change intended.

Link: https://lore.kernel.org/r/20230824193712.542167-4-helgaas@kernel.org


Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>