Update /debug/tracing/README

Some of the tracers have been renamed, which was not updated in the in-kernel
run-time README file. Update it.
Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
LKML-Reference: <200903231158.32151.knikanth@suse.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/trace/trace.c

@@ -2369,9 +2369,9 @@ static const char readme_msg[] =
 	"# mkdir /debug\n"
 	"# mount -t debugfs nodev /debug\n\n"
 	"# cat /debug/tracing/available_tracers\n"
-	"wakeup preemptirqsoff preemptoff irqsoff ftrace sched_switch none\n\n"
+	"wakeup preemptirqsoff preemptoff irqsoff function sched_switch nop\n\n"
 	"# cat /debug/tracing/current_tracer\n"
-	"none\n"
+	"nop\n"
 	"# echo sched_switch > /debug/tracing/current_tracer\n"
 	"# cat /debug/tracing/current_tracer\n"
 	"sched_switch\n"