dw_pcie_disable_atu() was introduced by f8aed6ec ("PCI: dwc:
designware: Add EP mode support") and supported only the viewport version
of the iATU CSRs.

DW PCIe IP cores v4.80a and newer also support unrolled iATU/eDMA space.
Callers of dw_pcie_disable_atu(), including pci_epc_ops.clear_bar(),
pci_epc_ops.unmap_addr(), and dw_pcie_setup_rc(), don't work correctly when
it is enabled.

Add dw_pcie_disable_atu() support for controllers with unrolled iATU CSRs
enabled.

[bhelgaas: commit log]
Fixes: f8aed6ec ("PCI: dwc: designware: Add EP mode support")
Link: https://lore.kernel.org/r/20220624143428.8334-3-Sergey.Semin@baikalelectronics.ruTested-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: NSerge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: NRob Herring <robh@kernel.org>