of/pci: Add support for parsing PCI host bridge resources from DT

Provide a function to parse the PCI DT ranges that can be used to create a
pci_host_bridge structure together with its associated bus.

Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
[make io_base parameter optional]
Signed-off-by: Robert Richter <rrichter@cavium.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: Arnd Bergmann <arnd@arndb.de>
CC: Grant Likely <grant.likely@linaro.org>
CC: Rob Herring <robh+dt@kernel.org>
CC: Catalin Marinas <catalin.marinas@arm.com>
diff --git a/include/linux/of_pci.h b/include/linux/of_pci.h
index 71062e9..1fd207e 100644
--- a/include/linux/of_pci.h
+++ b/include/linux/of_pci.h
@@ -52,6 +52,12 @@
 }
 #endif
 
+#if defined(CONFIG_OF_ADDRESS)
+int of_pci_get_host_bridge_resources(struct device_node *dev,
+			unsigned char busno, unsigned char bus_max,
+			struct list_head *resources, resource_size_t *io_base);
+#endif
+
 #if defined(CONFIG_OF) && defined(CONFIG_PCI_MSI)
 int of_pci_msi_chip_add(struct msi_chip *chip);
 void of_pci_msi_chip_remove(struct msi_chip *chip);