PCI/ACPI: Fix acpi_pci_set_power_state() debug message

If PCI_D3cold is passed to acpi_pci_set_power_state() as the second
argument and there is no ACPI D3cold support for the given device, the
debug message will state that the device power state has been changed to
D3cold, while in fact it will be D3hot, because acpi_device_set_power()
falls back to D3hot automatically if D3cold is not supported without
returning an error.

To address this issue, modify the debug message to print the current power
state of the target PCI device's ACPI companion instead of printing the
target power state, which may not reflect the real final power state of the
device.

Link: https://lore.kernel.org/r/4319486.LvFx2qVVIh@kreacher


Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Krzysztof Wilczyński <kw@linux.com>