Revert "sched/autogroup: Fix crash on reboot when autogroup is disabled"

Revert "sched/autogroup: Fix crash on reboot when autogroup is disabled"

This reverts commit f8e550c97586e855ad057f9bcac3bd1ea0e30e91,
because the underlying autogroups bug got fixed upstream in
a better way, via:

  e25136d64990 Revert "sched, autogroup: Stop going ahead if autogroup is disabled"

Cc: Mike Galbraith <efault@gmx.de>
Cc: Yong Zhang <yong.zhang0@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>