PCI: Use pbus_select_window() during BAR resize

Prior to a BAR resize, __resource_resize_store() loops through the normal
resources of the PCI device and releases those that match to the flags of
the BAR to be resized. This is necessary to allow resizing also the
upstream bridge window as only childless bridge windows can be resized.

While the flags check (mostly) works (if corner cases are ignored), the
more straightforward way is to check if the resources share the bridge
window. Change __resource_resize_store() to do the check using
pbus_select_window().

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://patch.msgid.link/20250829131113.36754-16-ilpo.jarvinen@linux.intel.com