PCI: Remove __weak tag from pci_register_io_range()

pci_register_io_range() has only one definition, so there is no need for
the __weak attribute.  Remove it.
Tested-by: Ndann frazier <dann.frazier@canonical.com>
Signed-off-by: NGabriele Paoloni <gabriele.paoloni@huawei.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>

drivers/pci/pci.c

@@ -3455,7 +3455,7 @@ static DEFINE_SPINLOCK(io_range_lock);
  * Record the PCI IO range (expressed as CPU physical address + size).
  * Return a negative value if an error has occured, zero otherwise
  */
-int __weak pci_register_io_range(phys_addr_t addr, resource_size_t size)
+int pci_register_io_range(phys_addr_t addr, resource_size_t size)
 {
 	int err = 0;