Update meta connector types enum

This adds the 4 new connector types that mutter didn't know about from
drm_mode.h in the kernel.

Noticed because mutter kept crashing when plugging in a USB-C adapter to
use an external monitor.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2577>

src/backends/meta-output.h

@@ -60,6 +60,10 @@ typedef enum
   META_CONNECTOR_TYPE_eDP = 14,
   META_CONNECTOR_TYPE_VIRTUAL = 15,
   META_CONNECTOR_TYPE_DSI = 16,
+  META_CONNECTOR_TYPE_DPI = 17,
+  META_CONNECTOR_TYPE_WRITEBACK = 18,
+  META_CONNECTOR_TYPE_SPI = 19,
+  META_CONNECTOR_TYPE_USB = 20,
 
   META_CONNECTOR_TYPE_META = 1000,
 } MetaConnectorType;