mesa/*: use an internal enum for tessellation primitive types.

To avoid dragging gl.h into places it has no business being,
defined tessellation primitive mode to an enum.

This has a lot of fallout all over the place.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14605>

src/gallium/drivers/iris/iris_context.h

@@ -228,7 +228,7 @@ struct iris_vs_prog_key {
 struct iris_tcs_prog_key {
    struct iris_vue_prog_key vue;
 
-   uint16_t tes_primitive_mode;
+   enum tess_primitive_mode _tes_primitive_mode;
 
    uint8_t input_vertices;