ftrace: remove trace array ctrl

Impact: remove obsolete variable in trace_array structure

With the new start / stop method of ftrace, the ctrl variable
in the trace_array structure is now obsolete. Remove it.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index e980b87..8693b7a 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -44,14 +44,12 @@
 
 static void function_trace_init(struct trace_array *tr)
 {
-	if (tr->ctrl)
-		start_function_trace(tr);
+	start_function_trace(tr);
 }
 
 static void function_trace_reset(struct trace_array *tr)
 {
-	if (tr->ctrl)
-		stop_function_trace(tr);
+	stop_function_trace(tr);
 }
 
 static void function_trace_start(struct trace_array *tr)