This backports the third version [1], which is awaiting upstream merge. It
adds support for watchdog max6370, which is connected via GPIO. It
is useful primarily for P2020 RDB and Turris 1.x routers, which are
not yet supported.
[1] https://www.spinics.net/lists/linux-watchdog/msg23299.html
Signed-off-by: Josef Schlehofer <pepe.schlehofer@gmail.com>
