sched/headers: Remove <linux/rculist.h> from <linux/sched.h>

We don't actually need the full rculist.h header anymore, include
the smaller rcupdate.h header instead.

Acked-by: Linus Torvalds <[e-mail]>
Cc: Mike Galbraith <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Signed-off-by: Ingo Molnar <[e-mail]>

include/linux/sched.h

···
 #include <linux/signal_types.h>
 #include <linux/pid.h>
 #include <linux/seccomp.h>
-#include <linux/rculist.h>
+#include <linux/rcupdate.h>
 
 #include <linux/resource.h>
 #include <linux/hrtimer.h>