PCI/ACPI: Advertise _HPX Type 3 support via _OSC

_OSC now has a way to inform firmware that OS has the capability to
interpret _HPX Type 3 setting records.  This was added by the following
PCI Firmware Specification ECN:

  ECN:  _HPX and PCIe Completion Timeout related _OSC Enhancements
  Date:	September 12, 2018
  Affected Document: PCI Firmware Specification, Rev. 3.2

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>