sched: Rename sched.c as sched/core.c in comments and Documentation

Most of the stuff from kernel/sched.c was moved to kernel/sched/core.c long time
back and the comments/Documentation never got updated.

I figured it out when I was going through sched-domains.txt and so thought of
fixing it globally.

I haven't crossed check if the stuff that is referenced in sched/core.c by all
these files is still present and hasn't changed as that wasn't the motive behind
this patch.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/cdff76a265326ab8d71922a1db5be599f20aad45.1370329560.git.viresh.kumar@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/arch/ia64/kernel/head.S b/arch/ia64/kernel/head.S
index 9be4e49..991ca33 100644
--- a/arch/ia64/kernel/head.S
+++ b/arch/ia64/kernel/head.S
@@ -1035,7 +1035,7 @@
  * Return a CPU-local timestamp in nano-seconds.  This timestamp is
  * NOT synchronized across CPUs its return value must never be
  * compared against the values returned on another CPU.  The usage in
- * kernel/sched.c ensures that.
+ * kernel/sched/core.c ensures that.
  *
  * The return-value of sched_clock() is NOT supposed to wrap-around.
  * If it did, it would cause some scheduling hiccups (at the worst).