tracing: Have error path in predicate_parse() free its allocated memory

In predicate_parse, there is an error path that is not going to
out_free instead it returns directly which leads to a memory leak.

Link: http://lkml.kernel.org/r/20190920225800.3870-1-navid.emamdoost@gmail.com

Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

kernel/trace/trace_events_filter.c

@@ -452,8 +452,10 @@ predicate_parse(const char *str, int nr_parens, int nr_preds,
 
 		switch (*next) {
 		case '(':					/* #2 */
-			if (top - op_stack > nr_parens)
-				return ERR_PTR(-EINVAL);
+			if (top - op_stack > nr_parens) {
+				ret = -EINVAL;
+				goto out_free;
+			}
 			*(++top) = invert;
 			continue;
 		case '!':					/* #3 */