vrend: remove stale comment

We no longer fall back here, as we've already tried glGetTexImage and
failed in the case where that's possible.

Signed-off-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Reviewed-by: Gurchetan Singh <gurchetansingh@chromium.org>

src/vrend_renderer.c

@@ -6999,7 +6999,6 @@ static int vrend_transfer_send_readonly(struct vrend_resource *res,
       return 0;
    }
 
-   /* Fallback to getteximage, will probably fail on GLES. */
    return -1;
 }