tracing: Fix small merge bug

During the 3.10 merge, a conflict happened and the resolution was
almost, but not quite, correct. An if statement was reversed.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
[ Duh. That was just silly of me  - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/trace/trace.c

@@ -904,7 +904,7 @@ update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
 		return;
 
 	WARN_ON_ONCE(!irqs_disabled());
-	if (tr->allocated_snapshot) {
+	if (!tr->allocated_snapshot) {
 		/* Only the nop tracer should hit this when disabling */
 		WARN_ON_ONCE(tr->current_trace != &nop_trace);
 		return;