of: Export of_pci_range_to_resource()

Some PCIe host drivers parse of_pci_range from device tree and convert
it to resources. Export of_pci_range_to_resource() to allow PCIe host
drivers to be compiled as loadable kernel module.

Signed-off-by: Manikanta Maddireddy <mmaddireddy@nvidia.com>
[lorenzo.pieralisi@arm.com: rewrote commit log]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Rob Herring <robh@kernel.org>