watchdog: introduce watchdog_suspend() and watchdog_resume()

watchdog: introduce watchdog_suspend() and watchdog_resume()

This interface can be utilized to deactivate the hard and soft lockup
detector temporarily.  Callers are expected to minimize the duration of
deactivation.  Multiple deactivations are allowed to occur in parallel but
should be rare in practice.

[[email protected]: remove unneeded static initialization]
Signed-off-by: Ulrich Obergfell <[email protected]>
Reviewed-by: Aaron Tomlin <[email protected]>
Cc: Guenter Roeck <[email protected]>
Cc: Don Zickus <[email protected]>
Cc: Ulrich Obergfell <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Chris Metcalf <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Ingo Molnar <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>