acpi_pci: Add quirk for PSTAT_PME-before-detach

In order to signal to Graviton [123] systems that a device is ready
to be "ejected" (after a detach request is made via the EC2 API) we
need to set PCIM_PSTAT_PME to 1 and PCIM_PSTAT_PMEENABLE to 0. We are
not aware of any rationale for this requirement beyond "another OS
kernel happens to do this", i.e. this is effectively bug-for-bug
compatibility.

Arguably this should be done by the ACPI _EJ0 method on these systems,
but it is not.

Create a new ACPI_Q_CLEAR_PME_ON_DETACH quirk and set it in EC2 AMIs,
and add the PCI register write to acpi_pci_device_notify_handler when
that quirk is set.

Reviewed by: jhb
MFC after: 1 month
Sponsored by: Amazon
Differential Revision: https://reviews.freebsd.org/D49146

(cherry picked from commit d70bac252d30adec4feba0c866dabe2c16a756d9)