watchdog: Move pretimeout governor configuration up

Watchdog pretimeout configuration was at the end of the Kconfig
file, after individual watchdog drivers, and thus easy to miss.
Move it right after basic watchdog option declarations.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>