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

We are going to split <linux/sched/task.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/task.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 <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Signed-off-by: Ingo Molnar <[email protected]>

Author: Ingo Molnar

arch/alpha/kernel/process.c

@@ -12,6 +12,7 @@
 #include <linux/module.h>
 #include <linux/sched.h>
 #include <linux/sched/debug.h>
+#include <linux/sched/task.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/smp.h>

arch/arc/kernel/process.c

@@ -11,6 +11,8 @@
 #include <linux/errno.h>
 #include <linux/module.h>
 #include <linux/sched.h>
+#include <linux/sched/task.h>
+
 #include <linux/mm.h>
 #include <linux/fs.h>
 #include <linux/unistd.h>