PCI: mvebu: Set PCI_BRIDGE_EMUL_NO_IO_FORWARD when IO is unsupported

This will make PCI bridge to return zeros when accessing IO base and limit
registers, as required by PCIe base specification.

This allows to remove adhoc checks around mvebu_pcie_handle_iobase_change()
function for unsupported IO ranges. PCI_BRIDGE_EMUL_NO_IO_FORWARD ensures
that there will be no non-zeros write to IO registers when IO is not
supported.

Link: https://lore.kernel.org/r/20220104153529.31647-8-pali@kernel.org


Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Rob Herring <robh@kernel.org>