pci: pcie-brcmstb: Fix inbound window configurations

pci: pcie-brcmstb: Fix inbound window configurations

So far we've assumed a fixed configuration for inbound windows as we had
a single user for this controller. But the controller's DMA constraints
were improved starting with BCM2711's B1 revision of the SoC, notably
available in CM4 and Pi400. They allow for wider inbound windows. We can
now cover the whole address space, whereas before we where limited to
the lower 3GB.

This information is passed to us through DT's 'dma-ranges' property and
it's specially important for us to honor it since some interactions with
the board's co-processor assume we're doing so (specifically the XHCI
firmware load operation, which is handled by the co-processor after
u-boot has correctly configured the PCIe controller).

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Tested-by: Peter Robinson <pbrobinson@gmail.com>
Signed-off-by: Matthias Brugger <mbrugger@suse.com>