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_sysprof.c b/kernel/trace/trace_sysprof.c
index 8097430..05f7534 100644
--- a/kernel/trace/trace_sysprof.c
+++ b/kernel/trace/trace_sysprof.c
@@ -265,14 +265,12 @@
 {
 	sysprof_trace = tr;
 
-	if (tr->ctrl)
-		start_stack_trace(tr);
+	start_stack_trace(tr);
 }
 
 static void stack_trace_reset(struct trace_array *tr)
 {
-	if (tr->ctrl)
-		stop_stack_trace(tr);
+	stop_stack_trace(tr);
 }
 
 static struct tracer stack_trace __read_mostly =