PCI: rcar Gen2: Request host bridge window resources

Request host bridge window resources so they appear in ioport_resource and
iomem_resource and are reflected in /proc/ioports and /proc/iomem.

Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>