microblaze/PCI: Clip bridge windows to fit in upstream windows

Every PCI-PCI bridge window should fit inside an upstream bridge window
because orphaned address space is unreachable from the primary side of the
upstream bridge.  If we inherit invalid bridge windows that overlap an
upstream window from firmware, clip them to fit and update the bridge
accordingly.

[bhelgaas: changelog]
Link: https://bugzilla.kernel.org/show_bug.cgi?id=85491


Reported-by: Marek Kordik <kordikmarek@gmail.com>
Fixes: 5b285415 ("PCI: Restrict 64-bit prefetchable bridge windows to 64-bit resources")
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: Michal Simek <monstr@monstr.eu>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Sebastian Ott <sebott@linux.vnet.ibm.com>