drm: Fix wrong kfree() in managed resource usage example

The example code showing how to use the managed resource API calls
kfree() on the wrong pointer. Fix it.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20200402095325.5266-1-laurent.pinchart+renesas@ideasonboard.com

drivers/gpu/drm/drm_drv.c

@@ -305,7 +305,7 @@ void drm_minor_release(struct drm_minor *minor)
  *
  *		ret = devm_drm_dev_init(&pdev->dev, drm, &driver_drm_driver);
  *		if (ret) {
- *			kfree(drm);
+ *			kfree(priv);
  *			return ret;
  *		}
  *		drmm_add_final_kfree(drm, priv);