monitor: Allow DPI connectors to be built-in displays

Needed for the Pinenote built-in display to be detected by Mutter
https://pine64.org/devices/pinenote/

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3067>

src/backends/meta-monitor.c

@@ -402,6 +402,7 @@ meta_monitor_is_laptop_panel (MetaMonitor *monitor)
     case META_CONNECTOR_TYPE_eDP:
     case META_CONNECTOR_TYPE_LVDS:
     case META_CONNECTOR_TYPE_DSI:
+    case META_CONNECTOR_TYPE_DPI:
       return TRUE;
     default:
       return FALSE;