Documentation: PM: Update platform_pci_wakeup_init() reference

platform_pci_wakeup_init() was removed by d2e5f0c ("ACPI / PCI: Rework
the setup and cleanup of device wakeup") but was still mentioned in the
documentation.

Update the doc to refer to pci_acpi_setup(), which does the equivalent
work.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Dhruva Gole <d-gole@ti.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Documentation/power/pci.rst

@@ -333,7 +333,7 @@ struct pci_dev.
 The PCI subsystem's first task related to device power management is to
 prepare the device for power management and initialize the fields of struct
 pci_dev used for this purpose.  This happens in two functions defined in
-drivers/pci/pci.c, pci_pm_init() and platform_pci_wakeup_init().
+drivers/pci/, pci_pm_init() and pci_acpi_setup().
 
 The first of these functions checks if the device supports native PCI PM
 and if that's the case the offset of its power management capability structure