PCI: rpadlpar: Make functions static

PCI: rpadlpar: Make functions static

The sparse tool report build warnings as follows:

  drivers/pci/hotplug/rpadlpar_core.c:355:5: warning: symbol 'dlpar_remove_pci_slot' was not declared. Should it be static?
  drivers/pci/hotplug/rpadlpar_core.c:461:12: warning: symbol 'rpadlpar_io_init' was not declared. Should it be static?
  drivers/pci/hotplug/rpadlpar_core.c:473:6: warning: symbol 'rpadlpar_io_exit' was not declared. Should it be static?

Those functions are not used outside of this file, so mark them static.

Also mark rpadlpar_io_exit() as __exit.

Link: https://lore.kernel.org/r/20200721151735.41181-1-weiyongjun1@huawei.com
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>