sched/autogroup: Remove unnecessary #ifdef guards

Since commit:

  029632fbb7b7 ("sched: Make separate sched*.c translation units")

autogroup is a separate translation unit built from the Makefile and
thus no longer needs its content wrapped with #ifdef CONFIG_SCHED_AUTOGROUP.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1429116678-17000-1-git-send-email-tklauser@distanz.ch
Signed-off-by: Ingo Molnar <mingo@kernel.org>