tracing: ftrace_event_is_function() can return boolean

Make ftrace_event_is_function() return bool to improve readability
due to this particular function only using either one or zero as its
return value.

No functional change.

Link: http://lkml.kernel.org/r/1443537816-5788-9-git-send-email-bywxiaobai@163.com

Signed-off-by: Yaowei Bai <bywxiaobai@163.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 89ffdaf..be2126f 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -873,7 +873,7 @@
 #define ftrace_destroy_filter_files(ops) do { } while (0)
 #endif /* CONFIG_FUNCTION_TRACER && CONFIG_DYNAMIC_FTRACE */
 
-int ftrace_event_is_function(struct trace_event_call *call);
+bool ftrace_event_is_function(struct trace_event_call *call);
 
 /*
  * struct trace_parser - servers for reading the user input separated by spaces