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

Commit c7a75d07 ("PCI: xgene: Fix IB window setup") tried to
fix the damages that 6dce5aa5 ("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 6dce5aa5 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/YjN8pT5e6/8cRohQ@xps13.dannf
Link: https://lore.kernel.org/r/20220321104843.949645-3-maz@kernel.org
Fixes: c7a75d07 ("PCI: xgene: Fix IB window setup")
Signed-off-by: NMarc Zyngier <maz@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: stable@vger.kernel.org
Cc: Rob Herring <robh@kernel.org>
Cc: Toan Le <toan@os.amperecomputing.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Krzysztof Wilczyński <kw@linux.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Stéphane Graber <stgraber@ubuntu.com>
Cc: dann frazier <dann.frazier@canonical.com>

drivers/pci/controller/pci-xgene.c

@@ -465,7 +465,7 @@ static int xgene_pcie_select_ib_reg(u8 *ib_reg_mask, u64 size)
 		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;
 	}