The American Megatrends BIOS I am using can be configured to start the
Fintek watchdog prior to the UEFI payloads. To avoid BIOS updates that reset
this functionality going unnoticed, implement support for WDOG_HW_RUNNING.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>