sched/wait: Reimplement wait_event_freezable()

sched/wait: Reimplement wait_event_freezable()

Provide better implementations of wait_event_freezable() APIs.

The problem is with freezer_do_not_count(), it hides the thread from
the freezer, even though this thread might not actually freeze/sleep
at all.

Cc: [email protected]
Cc: Rafael Wysocki <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Len Brown <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Pavel Machek <[email protected]>
Cc: Rafael J. Wysocki <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>