sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h>

Add #include <linux/cred.h> dependencies to all .c files rely on sched.h
doing that for them.

Note that even if the count where we need to add extra headers seems high,
it's still a net win, because <linux/sched.h> is included in over
2,200 files ...

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>

security/keys/internal.h

@@ -13,6 +13,7 @@
 #define _INTERNAL_H
 
 #include <linux/sched.h>
+#include <linux/cred.h>
 #include <linux/key-type.h>
 #include <linux/task_work.h>
 #include <linux/keyctl.h>

security/keys/keyctl.c

@@ -18,6 +18,7 @@
 #include <linux/keyctl.h>
 #include <linux/fs.h>
 #include <linux/capability.h>
+#include <linux/cred.h>
 #include <linux/string.h>
 #include <linux/err.h>
 #include <linux/vmalloc.h>

security/keys/persistent.c

@@ -10,6 +10,8 @@
  */
 
 #include <linux/user_namespace.h>
+#include <linux/cred.h>
+
 #include "internal.h"
 
 unsigned persistent_keyring_expiry = 3 * 24 * 3600; /* Expire after 3 days of non-use */