tracing: Rename ftrace_define_fields_##call() to trace_event_define_fields_##call()

The name "ftrace" really refers to the function hook infrastructure. It
is not about the trace_events. The function ftrace_define_fields_##call()
is used to define how to process the trace_event fields. It has nothing to
do with function tracing. Rename it.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/include/trace/trace_events.h b/include/trace/trace_events.h
index d88bd0f..e27b87e 100644
--- a/include/trace/trace_events.h
+++ b/include/trace/trace_events.h
@@ -407,7 +407,7 @@
 #undef DECLARE_EVENT_CLASS
 #define DECLARE_EVENT_CLASS(call, proto, args, tstruct, func, print)	\
 static int notrace __init						\
-ftrace_define_fields_##call(struct trace_event_call *event_call)	\
+trace_event_define_fields_##call(struct trace_event_call *event_call)	\
 {									\
 	struct trace_event_raw_##call field;				\
 	int ret;							\