sched/headers: Prepare to move the task_lock()/unlock() APIs to <linux/sched/task.h>

But first update the code that uses these facilities with the
new header.

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>
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index 550e8b1..26a6daf 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -15,6 +15,7 @@
 #include <linux/atomic.h>
 #include <linux/binfmts.h>
 #include <linux/sched/coredump.h>
+#include <linux/sched/task.h>
 
 struct ctl_table_header;
 struct mempolicy;