events: Rename TRACE_EVENT_TEMPLATE() to DECLARE_EVENT_CLASS()

It is not quite obvious at first sight what TRACE_EVENT_TEMPLATE
does: does it define an event as well beyond defining a template?

To clarify this, rename it to DECLARE_EVENT_CLASS, which follows
the various 'DECLARE_*()' idioms we already have in the kernel:

  DECLARE_EVENT_CLASS(class)

    DEFINE_EVENT(class, event1)
    DEFINE_EVENT(class, event2)
    DEFINE_EVENT(class, event3)

To complete this logic we should also rename TRACE_EVENT() to:

  DEFINE_SINGLE_EVENT(single_event)

... but in a more quiet moment of the kernel cycle.

Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4B0E286A.2000405@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/trace/define_trace.h b/include/trace/define_trace.h
index 5d7d855..5acfb1e 100644
--- a/include/trace/define_trace.h
+++ b/include/trace/define_trace.h
@@ -71,7 +71,7 @@
 
 #undef TRACE_EVENT
 #undef TRACE_EVENT_FN
-#undef TRACE_EVENT_TEMPLATE
+#undef DECLARE_EVENT_CLASS
 #undef DEFINE_EVENT
 #undef DEFINE_EVENT_PRINT
 #undef TRACE_HEADER_MULTI_READ