mm, oom: fix uninitialized ret in task_will_free_mem()

mm, oom: fix uninitialized ret in task_will_free_mem()

    mm/oom_kill.c: In function `task_will_free_mem':
    mm/oom_kill.c:767: warning: `ret' may be used uninitialized in this function

If __task_will_free_mem() is never called inside the for_each_process()
loop, ret will not be initialized.

Fixes: 1af8bb43269563e4 ("mm, oom: fortify task_will_free_mem()")
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Geert Uytterhoeven <[email protected]>
Acked-by: Tetsuo Handa <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>