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

We are going to split <linux/sched/coredump.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/coredump.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>

kernel/cred.c

@@ -12,6 +12,7 @@
 #include <linux/cred.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
+#include <linux/sched/coredump.h>
 #include <linux/key.h>
 #include <linux/keyctl.h>
 #include <linux/init_task.h>

kernel/events/uprobes.c

@@ -28,6 +28,7 @@
 #include <linux/slab.h>
 #include <linux/sched.h>
 #include <linux/sched/mm.h>
+#include <linux/sched/coredump.h>
 #include <linux/export.h>
 #include <linux/rmap.h>		/* anon_vma_prepare */
 #include <linux/mmu_notifier.h>	/* set_pte_at_notify */

kernel/fork.c

@@ -14,6 +14,7 @@
 #include <linux/slab.h>
 #include <linux/sched/autogroup.h>
 #include <linux/sched/mm.h>
+#include <linux/sched/coredump.h>
 #include <linux/init.h>
 #include <linux/unistd.h>
 #include <linux/module.h>

kernel/ptrace.c

@@ -11,6 +11,7 @@
 #include <linux/export.h>
 #include <linux/sched.h>
 #include <linux/sched/mm.h>
+#include <linux/sched/coredump.h>
 #include <linux/errno.h>
 #include <linux/mm.h>
 #include <linux/highmem.h>

kernel/sys.c

@@ -52,6 +52,7 @@
 #include <linux/sched/autogroup.h>
 #include <linux/sched/loadavg.h>
 #include <linux/sched/mm.h>
+#include <linux/sched/coredump.h>
 #include <linux/rcupdate.h>
 #include <linux/uidgid.h>
 #include <linux/cred.h>

kernel/sysctl.c

@@ -63,6 +63,7 @@
 #include <linux/capability.h>
 #include <linux/binfmts.h>
 #include <linux/sched/sysctl.h>
+#include <linux/sched/coredump.h>
 #include <linux/kexec.h>
 #include <linux/bpf.h>
 #include <linux/mount.h>