PCI: rockchip-ep: Improve rockchip_pcie_ep_unmap_addr()

PCI: rockchip-ep: Improve rockchip_pcie_ep_unmap_addr()

There is no need to loop over all regions to find the memory window used
to map an address. We can use rockchip_ob_region() to determine the
region index, together with a check that the address passed as argument
is the address used to create the mapping. Furthermore, the
ob_region_map bitmap should also be checked to ensure that we are not
attempting to unmap an address that is not mapped.

Link: https://lore.kernel.org/r/20241017015849.190271-4-dlemoal@kernel.org
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>