FROMGIT: kfence: unconditionally use unbound work queue

Unconditionally use unbound work queue, and not just if wq_power_efficient
is true.  Because if the system is idle, KFENCE may wait, and by being run
on the unbound work queue, we permit the scheduler to make better
scheduling decisions and not require pinning KFENCE to the same CPU upon
waking up.

Link: https://lkml.kernel.org/r/20210521111630.472579-1-elver@google.com


Fixes: 36f0b35d ("kfence: use power-efficient work queue to run delayed work")
Signed-off-by: Marco Elver <elver@google.com>
Reported-by: Hillf Danton <hdanton@sina.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

Bug: 181822795
Test: Treehugger
(cherry picked from commit bc900b3d574f9a630e9d05cf61383e999ca3b091
 https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git

 akpm)
Signed-off-by: Alexander Potapenko <glider@google.com>
Change-Id: I5f2029cb8b95fd97851615608520add94c602a18