PCI: OF: Correct of_irq_parse_pci() documentation

530210c7 ("of/irq: Replace of_irq with of_phandle_args") changed the
of_irq_parse_pci() parameter type but didn't change the corresponding
documentation.  Update the function doc to match.

Link: https://lore.kernel.org/r/20190807132049.10304-1-lkundrak@v3.sk


Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>