Current implementations of Intel Thunderbolt controllers will go
into a low power mode when not in use.

Many machines containing these controllers also have a GPIO wired up
that can force the controller awake.  This is offered via a ACPI-WMI
interface intended to be manipulated by a userspace utility.

This mechanism is provided by Intel to OEMs to include in BIOS.
It uses an industry wide GUID that is populated in a separate _WDG
entry with no binary MOF.

This interface allows software such as fwupd to wake up thunderbolt
controllers to query the firmware version or flash new firmware.
Signed-off-by: NMario Limonciello <mario.limonciello@dell.com>
Reviewed-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: NYehezkel Bernat <yehezkel.bernat@intel.com>
Signed-off-by: NDarren Hart (VMware) <dvhart@infradead.org>
[andy fixed merge conflicts and bump kernel version for ABI]
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>