ARM: integrator: basic PCIv3 device tree support

This registers the memory ranges for I/O, non-prefetched and
prefetched memory and configuration space for the PCIv3 bridge
and let us fetch these basic memory resources from the device
tree in the device tree boot path. Remove the stepping stone
platform device. This is an either/or approach - the platform
data path is mutually exclusive to the plain platform data
path and provided addresses from the device tree have to be
correct.

This adds the interrupt-map property to the PCIv3 DTS file
and makes the bridge obtain mappings from the device tree.

Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>