sched/headers: Prepare for new header dependencies before moving code to <linux/sched/cpufreq.h>

We are going to split <linux/sched/cpufreq.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/cpufreq.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

drivers/cpufreq/cpufreq_governor.c

@@ -18,7 +18,6 @@
 
 #include <linux/export.h>
 #include <linux/kernel_stat.h>
-#include <linux/sched.h>
 #include <linux/slab.h>
 
 #include "cpufreq_governor.h"

drivers/cpufreq/cpufreq_governor.h

@@ -20,6 +20,7 @@
 #include <linux/atomic.h>
 #include <linux/irq_work.h>
 #include <linux/cpufreq.h>
+#include <linux/sched/cpufreq.h>
 #include <linux/kernel_stat.h>
 #include <linux/module.h>
 #include <linux/mutex.h>

drivers/cpufreq/cpufreq_ondemand.c

@@ -16,6 +16,7 @@
 #include <linux/percpu-defs.h>
 #include <linux/slab.h>
 #include <linux/tick.h>
+#include <linux/sched/cpufreq.h>
 
 #include "cpufreq_ondemand.h"
 

drivers/cpufreq/intel_pstate.c

@@ -19,7 +19,7 @@
 #include <linux/hrtimer.h>
 #include <linux/tick.h>
 #include <linux/slab.h>
-#include <linux/sched.h>
+#include <linux/sched/cpufreq.h>
 #include <linux/list.h>
 #include <linux/cpu.h>
 #include <linux/cpufreq.h>

include/linux/sched/cpufreq.h

+#ifndef _LINUX_SCHED_CPUFREQ_H
+#define _LINUX_SCHED_CPUFREQ_H
+
+#include <linux/sched.h>
+
+#endif /* _LINUX_SCHED_CPUFREQ_H */

kernel/sched/sched.h

@@ -7,6 +7,7 @@
 #include <linux/sched/wake_q.h>
 #include <linux/sched/signal.h>
 #include <linux/sched/mm.h>
+#include <linux/sched/cpufreq.h>
 #include <linux/u64_stats_sync.h>
 #include <linux/sched/deadline.h>
 #include <linux/kernel_stat.h>