drm/ast: Zero is missing in detect function

The function ast_get_modes() will also return 0, when it try to get the
edid, but it also do not get the edid.
Signed-off-by: Ainux.Wang <ainux.wang@gmail.com>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20210716015615.9150-1-ainux.wang@gmail.com

drivers/gpu/drm/ast/ast_mode.c

@@ -1298,7 +1298,7 @@ static enum drm_connector_status ast_connector_detect(struct drm_connector
 	int r;
 
 	r = ast_get_modes(connector);
-	if (r < 0)
+	if (r <= 0)
 		return connector_status_disconnected;
 
 	return connector_status_connected;