tracing: remove ftrace:function TRACE_EVENT_FL_USE_CALL_FILTER flag

TRACE_EVENT_FL_USE_CALL_FILTER flag in ftrace:functon event can be
removed. This flag was first introduced in commit
f306cc82a93d ("tracing: Update event filters for multibuffer").

Now, the only place uses this flag is ftrace:function, but the filter of
ftrace:function has a different code path with events/syscalls and
events/tracepoints. It uses ftrace_filter_write() and perf's
ftrace_profile_set_filter() to set the filter, the functionality of file
'tracing/events/ftrace/function/filter' is bypassed in function
init_pred(), in which case, neither call->filter nor file->filter is
used.

So we can safely remove TRACE_EVENT_FL_USE_CALL_FILTER flag from
ftrace:function events.

Link: http://lkml.kernel.org/r/1425367294-27852-1-git-send-email-hekuang@huawei.com

Signed-off-by: He Kuang <hekuang@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

kernel/trace/trace_export.c

@@ -177,7 +177,7 @@ struct ftrace_event_call __used event_##call = {			\
 	},								\
 	.event.type		= etype,				\
 	.print_fmt		= print,				\
-	.flags			= TRACE_EVENT_FL_IGNORE_ENABLE | TRACE_EVENT_FL_USE_CALL_FILTER, \
+	.flags			= TRACE_EVENT_FL_IGNORE_ENABLE,		\
 };									\
 struct ftrace_event_call __used						\
 __attribute__((section("_ftrace_events"))) *__event_##call = &event_##call;