If nop tracer is selected, some old entries from the previous tracer
could still be enqueued. Tracing have to be reset.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Steven Noonan <steven@uplinklabs.net>
Signed-off-by: NIngo Molnar <mingo@elte.hu>