tracing: Get trace_array ref counts when accessing trace files

commit 7b85af63034818e43aee6c1d7bf1c7c6796a9073 upstream.

When a trace file is opened that may access a trace array, it must
increment its ref count to prevent it from being deleted.

Reported-by: Alexander Lam <azl@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>