sched/autogroup: Rename auto_group.[ch] to autogroup.[ch]

The names are all 'autogroup', not 'auto_group' - so rename
the kernel/sched/auto_group.[ch] to match the existing
nomenclature.

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

kernel/sched/Makefile

@@ -19,7 +19,7 @@ obj-y += core.o loadavg.o clock.o cputime.o
 obj-y += idle_task.o fair.o rt.o deadline.o stop_task.o
 obj-y += wait.o swait.o completion.o idle.o
 obj-$(CONFIG_SMP) += cpupri.o cpudeadline.o topology.o
-obj-$(CONFIG_SCHED_AUTOGROUP) += auto_group.o
+obj-$(CONFIG_SCHED_AUTOGROUP) += autogroup.o
 obj-$(CONFIG_SCHEDSTATS) += stats.o
 obj-$(CONFIG_SCHED_DEBUG) += debug.o
 obj-$(CONFIG_CGROUP_CPUACCT) += cpuacct.o

kernel/sched/sched.h

@@ -1069,7 +1069,7 @@ static inline void sched_ttwu_pending(void) { }
 #endif /* CONFIG_SMP */
 
 #include "stats.h"
-#include "auto_group.h"
+#include "autogroup.h"
 
 #ifdef CONFIG_CGROUP_SCHED