pci: pci-uclass: Add multi entry support for memory regions

Enable PCI memory regions in ranges property to be of multiple entry.
This helps to add support for SoC's like OcteonTX/TX2 where every
peripheral is on PCI bus.

Signed-off-by: Suneel Garapati <sgarapati@marvell.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Bin Meng <bmeng.cn@gmail.com>