sched: Transform resched_task() into resched_curr()

We always use resched_task() with rq->curr argument.
It's not possible to reschedule any task but rq's current.

The patch introduces resched_curr(struct rq *) to
replace all of the repeating patterns. The main aim
is cleanup, but there is a little size profit too:

  (before)
	$ size kernel/sched/built-in.o
	   text	   data	    bss	    dec	    hex	filename
	155274	  16445	   7042	 178761	  2ba49	kernel/sched/built-in.o

	$ size vmlinux
	   text	   data	    bss	    dec	    hex	filename
	7411490	1178376	 991232	9581098	 92322a	vmlinux

  (after)
	$ size kernel/sched/built-in.o
	   text	   data	    bss	    dec	    hex	filename
	155130	  16445	   7042	 178617	  2b9b9	kernel/sched/built-in.o

	$ size vmlinux
	   text	   data	    bss	    dec	    hex	filename
	7411362	1178376	 991232	9580970	 9231aa	vmlinux

	I was choosing between resched_curr() and resched_rq(),
	and the first name looks better for me.

A little lie in Documentation/trace/ftrace.txt. I have not
actually collected the tracing again. With a hope the patch
won't make execution times much worse :)

Signed-off-by: Kirill Tkhai <tkhai@yandex.ru>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20140628200219.1778.18735.stgit@localhost
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt
index 2479b2a..4da4261 100644
--- a/Documentation/trace/ftrace.txt
+++ b/Documentation/trace/ftrace.txt
@@ -1515,7 +1515,7 @@
   <idle>-0       3d.h4    1us+:      0:120:R   + [003]  2448: 94:R sleep
   <idle>-0       3d.h4    2us : ttwu_do_activate.constprop.87 <-try_to_wake_up
   <idle>-0       3d.h3    3us : check_preempt_curr <-ttwu_do_wakeup
-  <idle>-0       3d.h3    3us : resched_task <-check_preempt_curr
+  <idle>-0       3d.h3    3us : resched_curr <-check_preempt_curr
   <idle>-0       3dNh3    4us : task_woken_rt <-ttwu_do_wakeup
   <idle>-0       3dNh3    4us : _raw_spin_unlock <-try_to_wake_up
   <idle>-0       3dNh3    4us : sub_preempt_count <-_raw_spin_unlock