tracing: Deprecate tracing_enabled for tracing_on

tracing_enabled should not be used, it is heavy weight and does not
do much in helping lower the overhead.

tracing_on should be used instead. Warn users to use tracing_on
when tracing_enabled is used as it will soon be removed from the
tracing directory.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index dc53ecb..8dc8da6 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2710,6 +2710,10 @@
 
 	mutex_lock(&trace_types_lock);
 	if (tracer_enabled ^ val) {
+
+		/* Only need to warn if this is used to change the state */
+		WARN_ONCE(1, "tracing_enabled is deprecated. Use tracing_on");
+
 		if (val) {
 			tracer_enabled = 1;
 			if (current_trace->start)