PCI: xgene: Revert "PCI: xgene: Fix IB window setup"

Commit c7a75d07827a ("PCI: xgene: Fix IB window setup") tried to
fix the damages that 6dce5aa59e0b ("PCI: xgene: Use inbound resources
for setup") caused, but actually didn't improve anything for some
plarforms (at least Mustang and m400 are still broken).

Given that 6dce5aa59e0b has been reverted, revert this patch as well,
restoring the PCIe support on XGene to its pre-5.5, working state.

Link: https://lore.kernel.org/r/YjN8pT5e6/[e-mail]
Link: https://lore.kernel.org/r/[e-mail]
Fixes: c7a75d07827a ("PCI: xgene: Fix IB window setup")
Signed-off-by: Marc Zyngier <[e-mail]>
Signed-off-by: Lorenzo Pieralisi <[e-mail]>
Cc: [e-mail]
Cc: Rob Herring <[e-mail]>
Cc: Toan Le <[e-mail]>
Cc: Lorenzo Pieralisi <[e-mail]>
Cc: Krzysztof Wilczyński <[e-mail]>
Cc: Bjorn Helgaas <[e-mail]>
Cc: Stéphane Graber <[e-mail]>
Cc: dann frazier <[e-mail]>

drivers/pci/controller/pci-xgene.c

···
 		return 1;
 	}
 
-	if ((size > SZ_1K) && (size < SZ_4G) && !(*ib_reg_mask & (1 << 0))) {
+	if ((size > SZ_1K) && (size < SZ_1T) && !(*ib_reg_mask & (1 << 0))) {
 		*ib_reg_mask |= (1 << 0);
 		return 0;
 	}