PCI: Add empty stub for pci_register_io_range()

Add an empty stub for pci_register_io_range() when !CONFIG_PCI. It's needed
to convert of_pci_range_to_resource() to use IS_ENABLED(CONFIG_PCI).

Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-pci@vger.kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20210527194547.1287934-2-robh@kernel.org

include/linux/pci.h

@@ -1772,6 +1772,10 @@ static inline int pci_request_regions(struct pci_dev *dev, const char *res_name)
 { return -EIO; }
 static inline void pci_release_regions(struct pci_dev *dev) { }
 
+static inline int pci_register_io_range(struct fwnode_handle *fwnode,
+					phys_addr_t addr, resource_size_t size)
+{ return -EINVAL; }
+
 static inline unsigned long pci_address_to_pio(phys_addr_t addr) { return -1; }
 
 static inline struct pci_bus *pci_find_next_bus(const struct pci_bus *from)