Revert "PCI/ASPM: Remove pcie_aspm_pm_state_change()"

Revert "PCI/ASPM: Remove pcie_aspm_pm_state_change()"

This reverts commit 08d0cc5f34265d1a1e3031f319f594bd1970976c.

Michael reported that when attempting to resume from suspend to RAM on ASUS
mini PC PN51-BB757MDE1 (DMI model: MINIPC PN51-E1), 08d0cc5f3426
("PCI/ASPM: Remove pcie_aspm_pm_state_change()") caused a 12-second delay
with no output, followed by a reboot.

Workarounds include:

  - Reverting 08d0cc5f3426 ("PCI/ASPM: Remove pcie_aspm_pm_state_change()")
  - Booting with "pcie_aspm=off"
  - Booting with "pcie_aspm.policy=performance"
  - "echo 0 | sudo tee /sys/bus/pci/devices/0000:03:00.0/link/l1_aspm"
    before suspending
  - Connecting a USB flash drive

Link: https://lore.kernel.org/r/[email protected]
Fixes: 08d0cc5f3426 ("PCI/ASPM: Remove pcie_aspm_pm_state_change()")
Reported-by: Michael Schaller <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Bjorn Helgaas <[email protected]>
Cc: <[email protected]>