nvme: use _cleanup_free_ type buffer for get-feature command

Reduce the buffer free calls.

Signed-off-by: Tokunori Ikegami <ikegami.t@gmail.com>

Author: ikegami-t

nvme.c

@@ -4642,8 +4642,8 @@ static int get_feature_id_changed(struct nvme_dev *dev, struct feat_cfg cfg,
 	int err_def = 0;
 	__u32 result;
 	__u32 result_def;
-	void *buf = NULL;
-	void *buf_def = NULL;
+	_cleanup_free_ void *buf = NULL;
+	_cleanup_free_ void *buf_def = NULL;
 
 	if (changed)
 		cfg.sel = 0;
@@ -4662,9 +4662,6 @@ static int get_feature_id_changed(struct nvme_dev *dev, struct feat_cfg cfg,
 	    (buf && buf_def && !strcmp(buf, buf_def)))
 		get_feature_id_print(cfg, err, result, buf);
 
-	free(buf);
-	free(buf_def);
-
 	return err;
 }