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/Documentation/spinlocks.txt b/Documentation/spinlocks.txt
index 9dbe885..97eaf57 100644
--- a/Documentation/spinlocks.txt
+++ b/Documentation/spinlocks.txt
@@ -137,7 +137,7 @@
 But when you do the write-lock, you have to use the irq-safe version. 
 
 For an example of being clever with rw-locks, see the "waitqueue_lock" 
-handling in kernel/sched.c - nothing ever _changes_ a wait-queue from
+handling in kernel/sched/core.c - nothing ever _changes_ a wait-queue from
 within an interrupt, they only read the queue in order to know whom to
 wake up. So read-locks are safe (which is good: they are very common
 indeed), while write-locks need to protect themselves against interrupts.