perf metric: Fix memory leak in expr__add_id function

Arnaldo found that we don't release value data in case the hashmap__set
fails. Releasing it in case of an error.
Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Clarke <pc@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20200719181320.785305-2-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/expr.c

@@ -47,6 +47,8 @@ int expr__add_id_val(struct expr_parse_ctx *ctx, const char *id, double val)
 	}
 	ret = hashmap__set(&ctx->ids, id, data_ptr,
 			   (const void **)&old_key, (void **)&old_data);
+	if (ret)
+		free(data_ptr);
 	free(old_key);
 	free(old_data);
 	return ret;