PCI: dwc: Move inbound and outbound windows to common struct

PCI: dwc: Move inbound and outbound windows to common struct

The number of inbound and outbound windows are defined by the h/w and
apply to both RC and EP modes, so move them to the appropriate struct.

Link: https://lore.kernel.org/r/20201105211159.1814485-16-robh@kernel.org
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>