watchdog: Fix reboot on W83627ehf chipset.

The watchdog driver for the SUPERIO chip winbond w83627ehf does not work.
If you open /dev/watchdog and write a character to /dev/watchdog then
the watchdog will be triggered. However the watchdog will not trigger
the hardware RESET after the timeout, because the watchdog has never been
enabled.

Signed-off-by: Herman Morsink Vollenbroek <h.morsinkvollenbroek@home.nl>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>