tracing: show event name in trace for TRACE_EVENT created events

Unlike TRACE_FORMAT() macros, the TRACE_EVENT() macros do not show
the event name in the trace file. Knowing the event type in the trace
output is very useful.

Instead of:

   task swapper:0 [140] ==> ntpd:3308 [120]

We now have:

   sched_switch: task swapper:0 [140] ==> ntpd:3308 [120]
Signed-off-by: Steven Rostedt <srostedt@redhat.com>

kernel/trace/trace_events_stage_2.h

@@ -57,7 +57,7 @@ ftrace_raw_output_##call(struct trace_iterator *iter, int flags)	\
 									\
 	field = (typeof(field))entry;					\
 									\
-	ret = trace_seq_printf(s, print);				\
+	ret = trace_seq_printf(s, #call ": " print);			\
 	if (!ret)							\
 		return TRACE_TYPE_PARTIAL_LINE;				\
 									\