backend/drm: call get_drm_connector_props() when creating connector

This function fetches property IDs. These don't change for the
lifetime of the connector. Instead of refreshing the property IDs
on hotplug (and leaving property IDs unset for disconnected
connectors), only fetch the property IDs when we create the
connector.

backend/drm/drm.c

@@ -1379,6 +1379,11 @@ static struct wlr_drm_connector *create_drm_connector(struct wlr_drm_backend *dr
 	wlr_conn->status = DRM_MODE_DISCONNECTED;
 	wlr_conn->id = drm_conn->connector_id;
 
+	if (!get_drm_connector_props(drm->fd, wlr_conn->id, &wlr_conn->props)) {
+		free(wlr_conn);
+		return false;
+	}
+
 	const char *conn_name =
 		drmModeGetConnectorTypeName(drm_conn->connector_type);
 	if (conn_name == NULL) {
@@ -1511,10 +1516,6 @@ static bool connect_drm_connector(struct wlr_drm_connector *wlr_conn,
 		wlr_log(WLR_ERROR, "Unknown subpixel value: %d", (int)drm_conn->subpixel);
 	}
 
-	if (!get_drm_connector_props(drm->fd, wlr_conn->id, &wlr_conn->props)) {
-		return false;
-	}
-
 	uint64_t non_desktop;
 	if (get_drm_prop(drm->fd, wlr_conn->id,
 				wlr_conn->props.non_desktop, &non_desktop)) {