PCI: Align extra resources for hotplug bridges properly

After division the extra resource space per hotplug bridge may not be
aligned according to the window alignment, so align it before passing it
down for further distribution.

Link: https://lore.kernel.org/r/20230131092405.29121-2-mika.westerberg@linux.intel.com


Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>