tracing: Remove orphaned function using_ftrace_ops_list_func().

Remove using_ftrace_ops_list_func() since it is no longer used.

Using ftrace_ops_list_func() has been introduced by commit 7eea4fce
("tracing/stack_trace: Skip 4 instead of 3 when using ftrace_ops_list_func")
as a helper function, but its caller has been removed by commit 72ac426a
("tracing: Clean up stack tracing and fix fentry updates").  So it is not
called anymore.

Link: http://lkml.kernel.org/r/153260904427.12474.9952096317439329851.stgit@devboxSigned-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

kernel/trace/ftrace.c

@@ -313,11 +313,6 @@ static void update_ftrace_function(void)
 	ftrace_trace_function = func;
 }
 
-int using_ftrace_ops_list_func(void)
-{
-	return ftrace_trace_function == ftrace_ops_list_func;
-}
-
 static void add_ftrace_ops(struct ftrace_ops __rcu **list,
 			   struct ftrace_ops *ops)
 {

kernel/trace/trace.h

@@ -937,7 +937,6 @@ void ftrace_destroy_function_files(struct trace_array *tr);
 void ftrace_init_global_array_ops(struct trace_array *tr);
 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func);
 void ftrace_reset_array_ops(struct trace_array *tr);
-int using_ftrace_ops_list_func(void);
 void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer);
 void ftrace_init_tracefs_toplevel(struct trace_array *tr,
 				  struct dentry *d_tracer);