PCI/ASPM: Warn when driver asks to disable ASPM, but we can't do it
Some devices have hardware problems related to using ASPM. Drivers for
these devices use pci_disable_link_state() to prevent their device from
entering L0s or L1. But on platforms where the OS doesn't have permission
to manage ASPM, pci_disable_link_state() doesn't actually disable ASPM.
Windows has a similar mechanism ("PciASPMOptOut"), and when the OS doesn't
have control of ASPM, it doesn't actually disable ASPM either.
This patch just adds a warning in dmesg about the fact that
pci_disable_link_state() is doing nothing.