perf parse-events: Fix memory leaks found on parse_events

Fix a memory leak found by applying LLVM's libfuzzer on parse_events().
Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: clang-built-linux@googlegroups.com
Link: http://lore.kernel.org/lkml/20200319023101.82458-1-irogers@google.com
[ split from a larger patch, use zfree() ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/parse-events.c

@@ -1482,6 +1482,7 @@ int parse_events_add_pmu(struct parse_events_state *parse_state,
 
 		list_for_each_entry_safe(pos, tmp, &config_terms, list) {
 			list_del_init(&pos->list);
+			zfree(&pos->val.str);
 			free(pos);
 		}
 		return -EINVAL;